IBM paid Bill Gates to create DOS for them.
https://en.m.wikipedia.org/wiki/DOS
I think Apple would have have been more successful longer. How computer history would have changed if Apple computers beat the Wintel? Steve Jobs would not have been fired from Apple and he would have been CEO of Apple longer before he died.
This is what I'm saying about success and circumstances
many companies where doing advances around that point in time. I was reading a book somewhere that some systems were even at the level of windows but failed to be popularized due to poor understanding of the public. same as with blockchain today