wrt the polls, I don’t think any of the issues are entirely true. Eg Evernote is easy to escape, Onenote less so. Physical storage formats are often the most intractable issue.
The huge advantage of plaintext, which is what has powered its expansion, is that it is much lighter on resources (space, processing, developer). This makes it desirable for phone apps, the web and search. It’s held back by the lack of common standards that are sufficient for all developers and users.