The only issue I've run into regarding old hardware support are with nVidia drivers (I have an old nVidia Goo 7700 GPU that isn't supported by driver versions past 304, which limits me to kernel 4.4 I believe), but that's not the Linux kernel's fault.
I'd rather the airspace be shut down for a few days than have a military laser accidentally hit a commercial jet. I'd prefer neither happen, of course.