Speed certainly wouldn't be there, but capabilities would. Plenty could get done on those old machines — most of it had to do with programmers having the imagination & skill to be able to shoehorn their ideas into spaces they weren't meant to be crammed into.

One memory this project brought to mind for me was a hack I came across which allowed simultaneously running DOS 3.3 & ProDOS on a 128k Apple II, giving each 64k (well, a little less due to overhead) & a way to switch between the two with a simple command. Two programs couldn't run at once, but one could step between the two OSes to run programs made for each pretty seamlessly. If this sort of thing was possible on basic consumer hardware, ten or twenty years of development would have led to many far more interesting & useful things.