[cmrdporcupine]

Not sure what you're defining platform computer, but yeah, I think you're right. Tramiel Sr. also never understood the concept of an evolving platform with forward compatibility. Each of the Commodore home computers under his watch were bespoke and unique and not really expandable.

Operating system at both Atari and Commodore was treated as an afterthought and didn't get ongoing development. At Atari they put very little investment into the operating system after the original launch, and not much into the hardware either.

Not until his sons took over. Under them, Atari did finally make moves in the early 90s to try to build a large growable ecosystem on what was started and to diversify but it was too late.