Starting September 30th, there’s going to be a tsunami of Android users looking for an alternative system fleeing this developer verification malware.
In your opinion, are things like post market OS and the rest of the Linux phone ecosystem ready to take on these new users?
You’re not wrong, but I wouldn’t say “largely”. It’s mostly the elements that guarantee them a niche in the market: their very good Android App Support, some of the UI, plus some carryover from the NOKIA days (but they have started opensourcing some of those apps).
The rest is a bog-standard Linux/systemd/wayland system with an rpm/libzypp based package manager.