This argument can't hold, how do you know rails isn't going to flip, how do you know linux won't flip. How do you know vim won't flip? I'm sure you have tens if nit hundreds of technologies in your stack that are open source and you never imagined they were going to flip. I have rearly used wp for clients, but i was never under the impression it could go sideways just like most stable software i use.
The biggest thing in that category was Mysql "flipping" with the Oracle purchase. But people quickly migrated to postgres (which more-or-less is the same for smallish projects) and MariaDB as a Mysql fork exists as well. And I'm sure some people just kept using Mysql as well without having to do anything.
For all the tech I listed here, I think Rails is the one that would be hardest to a drop-in replacement for. Everything else is "generic." Text editors (not that I particularly care if a text editor is updated frequently (or at all most of the time)) and nix-like environments are basically hot swappable.
But IME when something has some sort of custom environment and that's the only way to deal with it (dashboard, special IDE, etc.) that's when you have the biggest risk of having a bad time.
