Those changes you might list of what Apple has done don't come without other people's work. I mean, for example, Microsoft became the first big software company, it paved the way for just about every other software company, proving it could stand on it's own with just software. Because of their focus on that, they made computers 1000x more accessible to the vast majority of "regular" people and more importantly, most importantly actually, it made it a lot more accessible to developers with their operating system. In turn, it gave rise to countless other software companies after seeing the example set with Microsoft, that it could be done and it could be sustained. That's where it began to take off.
All of that happened from building on existing ideas, building on what others had achieved before them. I'm not doubting that Jobs didn't have a vision of the future of computers, but the way people are attributing most if not all of it's rampant success to that one person, yeah overblown is exactly the right word for it, because it's not exclusive to this topic. It is all enveloping, everything. One way or another, just about everything is developed serially. TCD is completely right in his post.
Slippery slope as anything that anyone has thought of can be traced back to the first splitting of a cell. There is a thing called "flash of genius", where someone takes something existing and reconfigures\assembles it into something conceptually different or functional. Those with the "flash of genius" get the credit.
There were many "software" companies much bigger than Microsoft before they became prominent. IBM, DEC, Adobe, Visicalc (hell they were pulling in a ton more than Microsoft did in the early 80's, who knew a spreadsheet was going to be the killer app for the IBM PC, too bad the developer never realized what he had).
Speaking of which, Microsoft only exists in the capacity it is know as today because IBM (a rich dad with connections, and a certain Warren Buffet has a major hand as well), went to Microsoft for compilers (which is what they were doing at the time). IBM did not want to be the sole provider of the PC market, just make money off of each PC sold, just as it does today.
IBM had the business market, could easily get into the , and made a cheaper computer. Some say they initially took a loss on all of the IBM PC's sold through 1988 just to get the market share. Let's say you are looking for a new computer, your work has an IBM PC, the stores you go to are dominated by IBM PC's, and the IBM PC is the cheapest option, what do you choose? That was 1/2 of the genius of IBM's plan. The other was to own patents on just about all of the components along with the foundries to make the components.
To say that Microsoft made anything easy, accessible, and compatible through the 80's and 90's is laughable. Remember how IBM got control of the market, Microsoft did similar by underselling to the PC manufactures. There were other DOS makers in the 80's and early 90's. And other GUI's that ran on DOS and on the IBM PC's and would run the same software. Also keep in mind that Microsoft fucked over IBM with the the whole OS/2 debacle (funny how the last of that code has finally left Windows...guess their punishment for that is up).