I think it comes down to risk tolerance. For an established company that wants to avoid upsetting users at all costs, CI/CD makes sense. But for a nimble 'move fast and break things' startup, it can steal dev time for very little upside.
Say a disaster happens and someone pushes to main without running tests, 9 times out of 10 it will be of ~zero consequence (either the code works first time, it was a cosmetic change that hardly affected users etc).
I know there are horror stories and CI/CD would have prevented some of those, but IME they're just not that common nor severe for small operations, and even when they happen, only a small subset are irreversible/unfixable.
That's not the purpose of a remote CI/CD. Your pipeline can be as strict or as loose as you wish. It's there to show you a log of the execution as it happened in a neutral environment (remote server).
Basically, what you are suggesting is that everyone advertises their tests/builds run on slack? Also when two devs merge their changes, who compile/tests the master branch?