Some time in the early-ish 90s when I was a student I worked at a tiny place doing software development, targeting various commercial Unixes. Development was done on a lowly 486 running some variant of SCO System V UNIX, and I vaguely recall that the cost of licensing the system with compilers was thousands of dollars (you had to pay a lot of money for each little feature of the OS too, like TCP, SMP, ...). Or it would have been, if it hadn't been for some guys at the little ISP next door who gave us a copy of GCC, which was a gateway to running Slackware Linux, which was pretty soon where all future development was done before transferring it over to customers' HPUX boxes or whatever.
I was just a kid catching the tail end of all that, but there are still a couple of hard-to-get-your-hands-on big iron Unixes like that; I've worked on most of them (ie those and many that are gone), and I must say it's surprising to me that, by now, you still can't just download an ISO and run it on qemu or whatever (actually you can, but it's probably illegal). I could forget about them entirely, if I didn't have to keep the open source stuff I work on working on them too, with limited access and no CI...
I was just a kid catching the tail end of all that, but there are still a couple of hard-to-get-your-hands-on big iron Unixes like that; I've worked on most of them (ie those and many that are gone), and I must say it's surprising to me that, by now, you still can't just download an ISO and run it on qemu or whatever (actually you can, but it's probably illegal). I could forget about them entirely, if I didn't have to keep the open source stuff I work on working on them too, with limited access and no CI...