These projects are not done to solve “real problems”, they are done as educational engineering challenges and playgrounds. Of course a modern microcontroller do

These projects are not done to solve “real problems”, they are done as educational engineering challenges and playgrounds. Of course a modern microcontroller does everything and much much more, but it is also extremely opaque, and even the ones considered “simple” nowadays might not be fully understandable in every single aspect by just a single person. Now, nothing prevents you from still using a 6502 based project for “real problems” as well, and it’s fun to use your pet project for something practical every once in a while, but that’s usually not the focus. The focus is learning, building, intentionally reinventing the wheel so to speak. In my previous comment to you, I mentioned how Ben Eater made a self-designed CPU in his excellent video series, before switching to the 6502 to explore higher abstraction layers. In that case it may be more obvious that the focus was on designing the CPU itself, not on any a priori application use case for it.