Bill Gates as an inventor

I am not sure it was him (and I am euphemising here). He basically have been busy creating cages for programmers (even if it wasn't intentional at the beginning) and actually it was the people who pushed software progression. What he did was the same as Jobs: he was (he is) exceptionally good at selling stuff, be that a real value or pure bullshit, and with that money he was able to push more stuff out to reach more people and to gather more money. He forced peple to use the same system to run their program in and that resulted a working economy which catalised software progression. This wasn't on purpose.
I do not think successful monetizing stuff should be counted as "invention".

Instead, I would mention CP/M by Digital Research (which was the basis of MS-DOS), Xerox labs (which have invented the Graphical User Interface as we know today, apart from the mouse and desktop computing in general), I would mention IBM (who have created the cheap computers for the masses from stuff you can buy anywhere on the market; maybe even that wasn't an invention by itself), and I could possibly go on with real inventions Gates grabbed (bought or stolen) and marketed.