Are you a retired DOS programmer? You keep stating the above as fact, but it's not. Devs no longer need to code to specific hardware (EGS vs VGA, Sound Blaster or built-in speaker, co-processor absent or present, etc) as the OS takes care of most of this behind the scenes. Even more advanced stuff like threading is usually taken care of by the OS, though obviously it requires serious skill to write properly threaded software.
In other words, we (PC developers) write to the APIs, not the hardware platform. That's not to say there won't be those occasional hardware-specific bugs that crop in, but the vast majority of bugs in ED have nothing to do with hardware. Same goes with the bad performance - it's baked into Odyssey's core rendering algorithms, and it should be agnostic of hardware except for the obvious performance scaling (a higher end graphics card should be able to push a higher resolution at greater framerate, obviously).
Disclaimer - I do understand that targeting a specific platform like a console allows the programmer to write advanced low-level graphic subroutines in high-performance C or even assembly, thus allowing my PS4 to perform above it's weight when running something like Horizons Zero Dawn, but that actually makes things even more difficult to port over to PC. Frontier needs to fix the basic render pipeline first, and then they can invent clever "hacks" on PS4 / XBox to compensate for that ancient hardware.