What will end up happening is the major content creators, the ones that have massive followings will treat YouTube as the "advertisement" to the other platform they are on. "Hey guys thanks for checking out my video, here's a small preview. To view the full version, check me out at <some_other_platform>.com!" It's similar to what the big ones did with monetization (turned off all monetization, and now do in-video ads or some donation platform). Once that happens, there will be enough traffic on the new platform for enough medium size players to test the waters, then the whole thing will topple down. The only thing YT will have left is existing content, of which the only task remaining will be a race to archive what is currently on there.

Unlike a real desert, everyone can still reach you in your internet desert, and eventually it can become an internet oasis.

Then again, maybe once that happens YT will actually start to become content-creator friendly again.