Sounds to me like lawyers got wind of it and were worried that NVIDIA might sue them because they paid to have it made. They would likely be concerned about this whether or not NVIDIA had a case.

I mean, you got my upvote already, but one big reason is that Robertson wanted to control all the manufacturing of the screws and the bits. Phillips licensed his patent out and let anyone make them just taking a tiny licensing fee. Made a fortune on volume. Robertson: good engineer, bad businessman.