Interesting that the article is written in the past tense. The big exodus isn't scheduled to happen until Oct 1st, and inertia being what it is, I expect most of the "community" to hang around to see what happens and then stay around when they see there's still the same ol' stuff happening. After all, it's not the tech or the site but the community and what the community produces.
You can more or less vendor lockin your backend, for a very short time, if you have a decent frontend app like chanu. That is being worked around extremely quickly and actively, and that likely explains the whole oct 1st thing.
Compare this with the schism of slashdot and soylentnews. There is no dominant frontend for slashdot other than chromium so the schism happened a little faster.