Sounds like you've experienced my #1 reason -- Drupal "Developers!"
There's a great many really competent people working in the Drupal community. But there are an awful lot of people selling themselves as Drupal developers who really don't have a clue about how best to make the system work in a supportable, maintainable way.
I agree with you -- if you're not comfortable using git, configuring servers, doing all the dev-ops stuff, you'd better make sure you have someone handy who is, and treat them well. That stuff is critical to the success of any large Drupal site. We started out with a strong Linux system administration background before ever getting into Drupal, and had full-time systems administrators administering servers for other companies as well as our own. We still call that role "Systems Administrator," though the people we have in it become Drupal devs as well -- perhaps dev-ops is a better job title for them (and I count myself as one of them...)
But then again, people come to us for security scans, performance and scaling consulting, and more, and one of our key products is an ongoing monthly maintenance plan -- we make money doing dev-ops work. So we take it seriously!