No one is getting locked out of their files created by an old version. There will be a migration path. The old code will be in git. Worst case, the spec is open, I can implement the spec myself in python, using pycryptodome and pyca/cryptography, it wouldn't be hard.

I trust his judgement much more than I trust the group that maintains gpg. Of course, actually, there is a community, Filippo is not working in a vacuum. Worst case, if Filippo stops maintaining it or makes bad decisions, someone else (or a group of people) will maintain it.