It is very shortsighted to assume that everyone collects cards in the same way you do. People are usually very hyped for full-art supporters and they retain decent prices - now these people have another level of rarity they can collect if they want to.
I don't think a lot of people are assuming that, though. I know that on here especially completionist people like myself are in a minority, this community is mainly people who play the TCG rather than collect. You're 100% right that if people want to collect them that they can. Doesn't mean I or anyone else is obligated to be happy or not voice their opinions on it.
But nobody is putting the gun to yours or anyone's head to get them. They are not playable pieces, you're not going to lose a tournament without having them. The only value of having them is having them.
You can criticize their look all you want - they do look goofy. But the game does not have to adhere to one specific type of collector at the cost of competitive and casual players, collectors, traders and game stores. I'd take 30+ Secret Rares over 8 regular holo Rares every day of the week.
Of course nobody's forcing anyone to get them. But at the same time, I'm pretty sure we got by fine for YEARS (with some bumps in the road, granted) without having these kinds of rarities and those sets pretty much never adhered to any certain type of PTCG fan. How is not having a third type of rarity going to cause a hindrance to players? What causes people to have a hard time accessing meta cards is a thing called supply and demand. When you have a low pull rate, meta cards are going to go for a lot until they become accessible through some means. If you want to benefit people who just play the game, then you put those kinds of cards in accessible products. And they're starting that. $18 Holo Rares still happen, that's a problem with set sizes. Jirachi was going for that much (and more) until the UN Battle Arena Deck because its rate was something like 1/2 boxes for the normal holo. There's SO many factors that determine prices. How much was the set printed? Overprinting is why XY cards are so cheap. What's the demand for it, either competitively or in the collector's side of things?
The main problem I personally have with rainbow cards is that they're just plain ugly to me. It's a cheap looking palette-swap. I don't really like the fact that nearly every single main-set GX got them because it was bloating these sets with things that I considered unappealing. Alternate-Art Tag Teams do the same thing, but the difference with those? They're incredibly appealing, as they all have great artwork. I'm sure I'd be fine with three rarities of cards if they all had that appeal.
You do realize it's absolutely terrible for the long-term value of each set, if it can be completed with a single booster box? You are not supposed to buy randomized packs in hope of getting the cards you need - that's called gambling.
This is why cheap, small sets are awful for everyone - there's no way to open anything of value. Every card you open from tournament prizes is trash, no powerseller can ever make their money back, people lose interest, game dies. Even worse, because they have no expensive counter-parts, cards that are playable in Standard rise to ridiculous double-digit prices and then immediately fall to 50 cents after they rotate out, draining everyone's resources and giving nothing in return.
The game is more popular than ever now. I am not saying that's 1:1 correlation, but I am saying that stores are Local Game Stores much more willing to stock Pokemon product. The EV is higher and "shiny" cards boost over-the-counter sales.
No set can be completed with a SINGLE box. A complete common/uncommon/rare set in old ones, sure. But even in HGSS which had really high pull rates, you still had to finish off the set by either opening more stuff or getting singles. BW sets were about half the size of what we get now, and yet a lot of those individual FA's and SR's still hold value. A perfect set should have both collectible AND playable (at it's time in rotation) appeal. Later XY did this well, and the only reason they're so cheap is because they're overprinted to hell.
I think you might be overvaluing the impact of these cards. A 1 per box secret rare that makes barely any difference doesn't benefit collectors and game stores as much as you think it does.
Cards that are overvalued in the competitive scene is partially the fault of the sellers. They're trying to strike while the iron is hot, and are making money off the high demand. The reason they fall down to a low price, is because the collector's side of things often aren't looking for that card as much-after the players are done with those cards, it falls into almost exclusively a collector's market, which usually is much different (apart from Reshizard, which is one of the few exceptions in recent times) This can be solved by making these cards more accessible to players in products, more preconstructed decks with staples for instance. especially trainers like how they've done with Cynthia.
Card A, let's say it's in high demand. it has three prints. Let's say there's 500 Regular Prints, 250 Full Art Prints, and 100 Rainbow Prints. Demand is 1000 of them.
The rainbow one only marginally increases the supply of all kinds of Card A's in supply, compared to the regular and Full Art Prints. Not enough to meet demand. It might drop the price of the regular one only so much if it's in demand, but sellers are still going to sell it as high as possible.
I perfectly understand why people might be disappointed with Rainbow supporters, for multiple reasons. That's a perfectly valid opinion to have, but ultimately it is selfish - it does not relate to the overall state of the game and is limited to your own personal experience - especially since that experience will be limited to simply passing on these cards, not being locked out of the game by inaccessible deck prices or having your store lose revenue from worthless packs. We all want to live in a perfect world where all perspectives are equal and we can engage with the game however we want - but in the real world, I would prioritize having cards accessible and my Local Game Store not closing down/not quitting PTCG over optional collectible pieces having collectible-level prices.
Just to put it in other words - if we were to follow your needs exclusively (not saying you actually want that), then every pack in a box would be a Detective Pikachu pack.
That's the same as saying that having problems with mechanics in Sword and Shield is selfish. People critique the things they love because they want it to be better. Like I said, I don't care if someone enjoys rainbow cards, that's their prerogative, if it's something that makes someone happy, great. But that doesn't invalidate my or other people's criticisms. I think they're unnecessary additions to these sets, that didn't need to happen. That's my opinion. I'm not going to collect them, but that doesn't mean my opinion is all of a sudden illegitimate because it doesn't adhere to what you think is beneficial to players/card shops. There's SO many ways to strike that balance between casual fan/player/collector that doesn't involve just printing more palette swaps. (and striking that balance, mind you, would benefit everybody moreso than just benefiting one or two parties)
If a hobby is popular, it's going to sell. My LGS has everything from WOTC to Sun and Moon cards and they ALL sell, because Pokemon is popular. The collector's side is just as legitimate and beneficial to these shops as the casual and competitive side is. Pokemon is popular as a game, as a hobby, as collectibles, and it's been booming with all different kinds of people for a while now. Cards from 10-15-20 years ago would not be selling and benefiting these shops if there weren't collectors willing to shell out money on them.
