You were obviously not there at the time. Bill Gates got rich because IBM signed the daftest contract in computer history from their point of view.
Yes: IBM - the company known for hiring the very best in legal expertise signed away their arms and legs
Why? - I would like to know that!
What I do know is that Bill Gates was a completely unknown school kid until he was brought to IBM's attention by his mother, who was a high-up at IBM. Digital Research was well known. When Garry Kidall did not believe IBM had sent people to see him, somehow Mrs Gates must have been on hand to say to the right person "Check out my son - he is a genius and has written and OS" probably having no idea of the difference between and OS and an interpreter. (Would your mum know the difference? Would she have in 1980?) (mine would, and I have some idea how rare that was). QDOS was known to Bill Gates, who had, indeed, written some software (and a few others) and he spotted an opportunity when it hit him right between the eyes!
Whether Bill Gates or his Dad (who was a very well known lawyer) wrote the contact with IBM, I don't know. Why IBM signed the contract without their lawyers reading it properly, I don't know. In my view the whole thing stinks. (Though I recognise that IBM's decision making was coloured by buffoons who thought they would be lucky to sell 10,000 PCs.
Here in the UK, most people involved in software at the time (like me) did almost nothing for the year that elapsed between rumours that IBM might make a PC, and the first one being delivered, because their employers wanted them to be instantly available to port the company's existing products to the PC - the entire industry knew it would be a game changer. Read the magazines from the time: It was like "Apple is going to make a phone that will run 3rd party apps" x 1,000!
Incidentally, Intel had a perfectly good OS at the time called ISIS but refused to sell it to anyone!
I also don't know why you need a GE225 to write BASIC, surely the most machine independent interpreter ever.
Disclaimer: I wrote an ISIS/CPM clone, but my employers refused to sell it because they said "No one would buy software written in the UK!" - and they were a UK software company"