Well I can't see Dovecot devs deciding to implement it if they keep reading comments like this dissuading the effort...

What advantage would they gain by implementing it?

There's three considerations

(a) is IMAP good / sufficient / fit for purpose

(b) if not, is there a better alternative available

(c) if there is, is it worth the development effort to support it.

If we assume the answers to (a) & (b) are NO & JMAP, then the benefits are included in those answers & only question remaining is (c). The person I was replying to seemed to be only arguing that the answer to (c) is NO.

(a) No (b) JMAP (c) Long term, probably.

Cyrus is a system like dovecot?