Comment by brudgers

run for ~50 years where the hardware will need to be replaced

If it needs to run for fifty years, specify hardware that has a long support cycle such as Mil-Spec.

That’s why the Z80 was around for so long and why so many companies in the 80’s and 90’s still deigned around it. (1)

If you let programmers drive system design, winding up with an “Amiga” in your certified design is a more probable outcome…

(1) there’s a moderate chance that new hardware that can run Z80 code will be around fifty years from now.