Eventually, things will probably whittle down to a handful of successful options, a la survival of the fittest.
I wonder if there's an example of a software category that went through something like that?
Doubt it. Most people aren't trying out a lot of these things.
There's always going to be more people who come up with their own ideas of how to take notes, making new note-taking applications.
They will reinvent each others' ideas again and again, maybe some _ideas_ will somehow persist and become pervasive, but always there will be new note-taking apps with every generation.
I am 100% agreed on this. I have used Evernote for many years and really hate the curse of commercial software that forces them to constantly fiddle and break things that their customers have come to rely on. Nevertheless, despite not loving it, I touch Evernote multiple times per hour almost every hour throughout my work day. I need a mobile app and quick sync between different apps, and that will be hard for an open-source effort or a one-person startup to achieve. I wonder if an open-source app could be built on top of a paid commercial sync service; I would gladly pay for that.
Anyway, I recommend checking it out to see if it meets your use case. It's been a while, but I believe it has the ability to import from Evernote, or at least read from whatever export format Evernote provides, something like that.
Personally I'm pretty happy with Apple Notes, though Bear is a close runner up.
I'm not sure why they don't go the Syncthing route of offering peer-to-peer note syncing.
It's still not Notes/One Note equivalent (I'm in your same boat) but it's the closer thing I've found to use with my Android and Linux.