Comment by TMWNN

If you don't want to believe me that Apple's drives worked and Tandy's didn't, consider why VisiCalc launched on the Apple II in 1979 despite Bricklin and Frankston intending to do so on the Model I,[1] because of the latter's far greater market share.

[1] Not only that, Dan Fylstra (founder of VisiCalc publisher Personal Software) was among the first people in the world to own the Commodore PET and the Model I, having reviewed both for BYTE