Probably old news but fascinating all the same - clearly it was a simpler time.
28K instructions / data ops for the 'OS' and all guest programs, with 4K words (also 16 bit) of memory mapped IO / device registers.
It's clear the entire system would have been constructed in what today might be thought of as a 'Minimum Viable Product' format. Powerful functions and operations, but focused on a very narrow tolerance for inputs. The intelligence of even 'dumb' terminals makes a ton of sense and this gives me a greater perspective of the relative power required for early laser printers (rasterizing vector graphics on the fly) in the 80s.
("When in doubt, use brute force" -- Ken Thompson).
I guess this is the coding equivalent of 1950s Nuclear Family nostalgia? Pining for something you'd hate if you had to suffer under it, idealizing the past, and ignoring how and why we got to modern times (the past sucked in a lot of ways).
The Alto ran a full-fledged mouse-driven GUI, IDE + programming language with rich class library, E-Mail, text-processing in 64KB memory (128KB RAM, half of that for the screen) and 2.5MB disk.