Why are hobbyist 21st century 8-bit computers so constrained?

I learned about a new DIY machine to me, the Cody Computer . It looks kind of fun, but once again, it does make me wonder why it&rsquo;s so constrained. Extremely low-res graphics, for instance. TBH I would have sneered at this for being low-end when I was about 13 years old. (Shortly before I got my first computer, a 48K ZX Spectrum.) Why isn&rsquo;t anyone trying to make an easy home-build…