Nitpick, but it was ultimately Xerox's ideas that defined the personal computer, with Apple just being the earliest to have massive success at bringing those ideas to market.
The figure in computing history I'd analogize Levitt to here would be Gary Kildall.
Kildall pioneered the concept of an open architecture with products from many competing vendors all implementing compatible standards and running the same OS. Ultimately, Microsoft stole his thunder, his company failed, and he died in relative obscurity, without the recognition he deserves for pioneering the modern industry.
The figure in computing history I'd analogize Levitt to here would be Gary Kildall. Kildall pioneered the concept of an open architecture with products from many competing vendors all implementing compatible standards and running the same OS. Ultimately, Microsoft stole his thunder, his company failed, and he died in relative obscurity, without the recognition he deserves for pioneering the modern industry.