There are a lot of decades old embedded systems out there. Every so often you hear about a big company still relying on floppy disks and other old tech, including major railways and airplane companies. Having the source code will help with debugging better than having to disassemble or other reverse engineering.
As someone who started in the deep end back in 2001 (My first distro was a Slackware derivative) I actually enjoyed the satisfaction of trying to get XFree86 to work and seeing all the available command line tools. Of course this was back in the Windows 98 days so I was already used to going into MS-DOS mode. My first computer was a Commodore 64 as well so didn’t get mollycoddled at all when learning to use a computer.