And I really fail to see why these are not OPEN preorders so that TPCi knows how much product to make and every customer gets what they want.
You make a good point about Open Preorders, but given that TPCI is ALREADY spinning its wheels to try and get cards off the printing press (as I previously mentioned), hitting record printing numbers to no avail, I extremely doubt that Pokémon would be able to print enough boxes in one round to put off scalpers AND satisfy all the customer requests. The backlog would still be significant, with the difference that the frustration of missing out would be replaced by the frustration of waiting indefinitely. Although, perhaps scalping wouldn't exist in an open preorder system since products would be made to demand?
Regardless, you know who the pre-order system DOESN'T satisfy? Kids. Kids who don't play the TCG competitively, know where to find the best product or how to get the best value, but just collect casually. Kids, who choose what cards they want to collect based off of simple personal preferences and not off of a long experience with the franchise or because a set is "rare" or "high value." Kids, who may give their parents a birthday or Christmas wishlist with a few TCG products on them, never suspecting that those products will not be readily available. The best case scenario for the small fry of the Pokémon universe is more product appearing on store shelves (and on websites for retailers like Target and Amazon), and as for the store shelves, we've seen some improvements lately.
It's just a collection of terrible decisions and a lack of care for their customers.
I wouldn't say they don't care about their customers. I've ordered off of Pokémon Center several times and always gotten good results.
As I mentioned before, businesses want to make money, and if too many people slip out of the Pokémon market, TPCI is going to want to try and get them back. Recently Pokémon GO players boycotted the game because Pokestop ranges were reduced to what they were before COVID; now they are as large as they were during the pandemic, presumably to stay that way indefinitely. Granted that was Niantic and not Pokémon GO. TPCI doesn't want to lose a significant portion of customers, and TPCI wants to make money, so TPCI is going to want to print as much product as can be sold and ensure that it gets into the hands of customers.
As for the current dilemna, all I can say is, the product is out of stock now, and unfortunately all that remains to be done is to wait. Waiting never comes easy; I know that myself. As I mentioned before, I once ordered the Champion's Path Special Pin Collection [Circhester] on GameStop and had to cancel the order when it never arrived. Now, if I want to, I can go to my local target and buy a couple of Dubwool V boxes and order a Lapras promo (which was the main draw of that specific collection) off of TCGPLAYER for $2.50 if I really want to get the Champion's Path experience. And guess what? I'm perfectly fine without that option. But it's there if I'm interested. This is a major inconvenience, and one might reasonably say an outrage, but it isn't the last opportunity to open a Celebrations Elite Trainer Box. Who knows? You MIGHT even find the ordinary one in-store on release date.
Couldn't you still get this Greninja in a booster pack?
No, because it's a PROMO, but for all we know the PROMO might sell for $5 (or it might sell for $15. It's too early to know how much any of the cards will retail for).