Before that the OS development was tightly coupled to hardware development. Booting an existing OS on a new device even with the same CPU required prior patching, configuration and re-implementation of the floppy drive driver. And it wasn't seen as odd because that's the way it was.
I don't think the problem is a lack of OS enthusiasts, we probably have more of them than at the time Linux was born. The problem is they're fighting an uphill battle against a swarm of slightly different CPUs and device trees and uncooperative vendors that do anything they can to lock the device.