Lol There are not enough gems from all the characters in this game to buy every pack at least once, it's less than half
https://www.reddit.com/r/DuelLinks/comments/c49l3p/discussion_5520_packs_276000_gems_461032/
Decks lose their relevance over time, so if your account is old you just run out of resources to keep playing.
And still some people say that this game is "free to play"
This game is so free that if you want to collect a complete collection, you can buy a car for the same money lol.
And most top decks contain cards from totally not free EX decks, that are released every month.
Yeah, it's not like you could just focus on a couple of boxes to build a competitive deck or anything. And it's a shame that level-up gems are the only gems we ever get, huh...
Realistically, it's not difficult to save up for a competitive deck if you're not an idiot, especially if you stick with that deck for more than like a month or two.
A deck very, very rarely gets outpowercrept within 2 months. Six Samurai are still a meta-worthy deck, even if they're no longer number 1 for example. It's also easy to avoid this by waiting for the next box/structure deck before committing to a deck to see if it did indeed change your mind.