There is also the fact that most of the resistance seems to be in the form of "zomg they [fixed] $OP-thing I'm going to fight my gm if they try to switch over the game I play in".I think your overestimating the magnitude of the changes. The Devs are going out of their way to make sure everything works together, specifically to avoid a split.
I've played with 2014 and playtest characters side by side without any issues. Simply trading out existing characters with their new versions each time it dropped (except the fist druid attempt, no one wanted to try that).
So in my experience, actually using it, half the people will grab the new stuff right away. The other half will decide there's not enough change to warrant buying another book. And 95%* will just continue playing their current campaign, together.
Then over the next decade, as campaigns end, characters die, and books are passed around, the second half will slowly switch.
*I am sure there will be a few people somewhere who dig their heals in.
That's not exactly a position within most groups that is capable of doing much more than maybe delaying the inevitable a bit without taking on a role that reveals why it was changed &runs their nose in it. Players making those kind of complaints are not typically known for taking on the gm role all that often (if ever)