Most are, implicitly at least. But at the time, there was definitely a period of transition with many shops continuing to use subversion for a while.

You should be able to pick up tools and learn on need. There are better version control systems than git - always have been, but git won despite being worse. (Git was massively better than what was popular before it won) if you can't learn git quick then you shouldn't program at all - there are much harder tools you will need to know and many are company or project specific

Just last year I migrated to Git a major code base that was still stuck in SVN. It's not even a legacy project, just a laggard. For some colleagues, this was their first time using Git on the job.