Notes provided an amazing platform. I think its fatal flaw was that it targeted unskilled developers. The result was a bunch of poorly made applications which were naturally hated by users. Also targeting unskilled developers resulted in a developer experience hostile to skilled software engineers so they went elsewhere.

25yrs ago, doing any kind of revision control or compare different "versions" of the same "database" was next to impossible IIRC. Then there were those "replication failures", sometimes trivial to fix, sometimes completely impossible to debug. And god forbid you did something to the default email template to make it more compatible with external IMAP clients...