VisiCorp was developing their VisiOn platform in the 1984-ish timeframe. They were bending heaven and earth to fit into 640K. Telling their corporate customers

VisiCorp was developing their VisiOn platform in the 1984-ish timeframe. They were bending heaven and earth to fit into 640K. Telling their corporate customers, "Buy another 512K of RAM" would probably have saved their company and let them ship a number of world-class productivity products, and given Windows some interesting competition. It's easy to second guess this stuff, on the other hand 512K of RAM was about $120 in 1985. We shipped the Atari ST with that much, when having that amount of memory on a Mac was pretty rare.