It seems rather popular to QQ about turtling on TT. Usually (and correct me if I'm wrong) the threads take one of two general routes:
1. "We pushed through inhibs, but the enemy team turtled, got a lucky ace, and won. Ergo TT is a broken map."
2.. "We pushed to the base, and ultimately won, but the enemy team's turtling delayed the process for some time. Ergo TT is a broken map."
Ok, cards on the table. In my humble opinion, these are both complete ****, and both for the same reason: until you destroy the nexus, you didn't win. Let me say that again: until you destroy the nexus and see that wonderful victory screen, YOU DID NOT WIN.
As in football (American version), until you cross into the end one, you did not score. There's a reason that area close to it is called the red zone--and "almost" doesn't get you through it. Or as in baseball, until you get strike three, it's not a strikeout. There is a reason strike two is far more common than strike three, and "almost" doesn't get that last pitch past the batter. "Almost" only counts in horseshoes and hand grenades (notice the absence of lol in that list).
Last point, and more of an afterthought: TT is not SR, and does not claim to be. What is game-winning on SR might not be on TT, and shouldn't necessarily be expected to be. Beach volleyball (2 people) is not played exactly the same as regular volleyball (6 people), and shouldn't be expected to be. If you're going to play TT, learn to deal with turtling. It can be beaten, and relatively easily if you know how. If you can't, and you lose to a turtling team, you didn't deserve to win.
To sum up: if you "deserve" to win, or if you've "already won," you'll see the victory screen. Until then, the game is not won. Period.
That is all. Peace and love fellow summoners!