@Card Slinger J
First off, sorry to everyone that this is responding to a post made about 10 posts before this one. When I said that some people would quit, I don't mean every single Lostgar player, or even just the Lostgar players who perform well with the deck. I meant the minority of players that'll build the deck purely as a way to become a top player in their area, and even then probably only 20% of them at the most.
For example if a player (especially one who's current performance is below average), spends however much it costs to build a Lostgar deck, and begins to perform well with the deck, and then it gets announced that lost world is banned from competitive play, that player may feel cheated, or just angry in general because their investment of Lost Worlds and Gengar Primes are now almost worthless, and quit because of it.
I can see your point as to how this is an unlikely scenario, as (thankfully) there's only a small number of players who behave like that. I also agree with you that doing something like that is stupid. If you put competitiveness behind the "fun factor" in your priorities when it comes to any card game, you're going to be hugely disappointed. Also, an eretta on Lost World could work well into making Lostgar a powerful, yet still balanced deck, but I think that if POP takes any action, it'll most likely be a ban.