Who? Where? for what?
You mentioned BeOS. Sorry, I love nostalgia too, but I have no idea what you're talking about. Out in AWS, GCP, Azure, DO -land... it's still going to be Ubuntu, Debian, CentOS, Windows, etc for a long time.
I'm still somewhat bothered that Apple let their server offering go. And yes, FreeBSD replaces Linux easily. Not everyone runs their stuff in the cloud. It's not the be-all and end-all. Serious non-IT businesses are still on mainframes, BSD, and other, and there are plenty of them. A friend of mine is a COBOL programmer for a large financial house, and he's set for as long as he wants to work there, and at almost $80hr (Texas), he's making better coin than most programmers here.
No, it doesn’t. Take any non trivial system running Linux and try to run it in FreeBSD. You may get it running in little time, however the number of issues you would have would be big.
Remember that the modern stack have multiple layers of complexity, Linux, your app, SomethingSQL, AnotherThingDb, Kubernetes, AWS/GCE/Azure, etc. Since FreeBSD is not the common choice to run those things you will probably hit a issue here, another issue there, a combination of issue in one layer with another, etc.
Yeah, this may say more about our current systems than anything, however to say that it is easy to substitute Linux with FreeBSD is simply not true.
For glue like kubernetes, yes, you're going to find differences or even lack of support for that specific tool. Ansible works pretty well, in my experience. But this is the more superficial stuff. If you're going to migrate for whatever reason, then updating the automation tooling around the systems you're managing is not that difficult.
These are but a few. Here in the Houston area, there are tons of FreeBSD/OpenBSD users.
Not sure about all programmers but I'm at $200 and I'm underpaid compared to my coworkers. Big telco.
Yes $200/h is underpaid, it should be what people working at Walmart get paid.
Yes, you're right, Ubuntu, Debian, CentOS etc. are the common systems in use for this purpose today. But, if you needed to, you could absolutely use FreeBSD as an alternative. And should there be pressure to drop any of these Linux systems for any reason, having alternatives right there you can switch to is very useful. As is avoiding vendor locking and ensuring there's meaningful competition.