Its sort of like how in a lot of universities when taking a computer architecture course, the focus is usually on MIPS or RISCV or LC-3 and not something like a modern x86_64 processor. Tons of books exists to teach computer architecture in these architectures. They are also small, compact, and straight forward. You can understand every thing in 6502 or simple MIPS processor from logic gates, instruction set and how pipelining instructions work and branch prediction. I could be wrong, but if I had to guess, not even an engineer at Intel can break down their current processors and have all of that fit into their head.
Retro stuff also presents a challenge. There is a guy who writes some crazy software for I believe the Mac-II. It can be a great test of skill to take an old machine have it capable of doing modern things, because it requires getting knee deep in the weeds on optimization and such. One issue I think we have in software is, modern machines are really powerful. To the point of even shitty un-optimized code in average use cases can run decently well. Targeting these kinds of machines can help build those skills in learning how to optimize because, well, you would actually have to optimize to get these older machines to do modern things.
Retro stuff also presents a challenge. There is a guy who writes some crazy software for I believe the Mac-II. It can be a great test of skill to take an old machine have it capable of doing modern things, because it requires getting knee deep in the weeds on optimization and such. One issue I think we have in software is, modern machines are really powerful. To the point of even shitty un-optimized code in average use cases can run decently well. Targeting these kinds of machines can help build those skills in learning how to optimize because, well, you would actually have to optimize to get these older machines to do modern things.