I agree entirely, and nicely put.

Aside from a distinct announce list, the same need could be met other ways, instead or in addition.

A stylized Subject on the announcement postings, or other attribute, documented as an official service that people could commit to code.

A release announcement file that's uploaded along with the files that marks the upload as a committed new release, rather than a transient state. That could be as simple as a symlink that always points to the current release.

An RSS feed of release announcements.

Others, I'm sure.

But whatever the mechanism, it'd be nice to have a channel that didn't require an alert human to monitor the development list.