Virtually endlessly. What they’re talking about is, AFAIK, the actual original (not actually original, but NES) Tetris. It was meant to be infinite, but at some point the numbers get too big to store, and the programming starts breaking down. Some games might be able to keep going indefinitely, just resetting/looping some numbers, and in modern games it might take years, centuries, or even universal lifetimes to reach that point, but almost all “infinite” games will break down at some point.
original Tetris was made on Electronika 60, very few people played that version.
they’re talking about the nintendo entertainment version of tetris, which is the most popular competitive version of tetris.
it’s the one that they play at the largest tournaments, and the tetris game with the most sought after world records, so i’m using that as my indicator. what would you say is the most popular version for competative play?