Because generally people picking the tools are not majority of dev. They are architects or Senior Developers who do enjoy learning new things.

Also, git generally does just work and most IDE/Source Control Systems take care of basic operation of pull/branch/commit/push/open PR.

I suppose. It might seem a bit perverse after all if the non-engaged, uninterested in coding, clock puncher devs got to make all the decisions.

Popular as in “everyone is using it”, not necessarily “everyone is fond of it”. How did Jira become so popular? The dynamics that lead to such outcomes are interesting, but hardly unusual.