Many seem to point at active authors and keep saying how the changes have made everyone post less, leave altogether, etc,

There is literally NO evidence of posts declining as a result of the fork.

See the green line on chart #4 here: https://steemit.com/steemit/@penguinpablo/weekly-steem-stats-report-monday-january-20-2020

Nor active accounts (chart #3 same link).

What both show is a continued declining trajectory essentially unchanged before and after the fork.

Comments per post (blue line, first chart) did show a big decline right after the fork. Without more data we can't say clearly what that means.