Without Gates I'd say that the world would be about as it is today, but our computers would all have little Apple icons on them. Jobs would be living in the enormous house, only the enormous house would be on an equally enormous estate in the Los Gatos hills of California.
Much as I find fault with some of Microsoft's practices I have to admit that the philanthropic ventures Bill and Melinda Gates are involved in now are to be admired as well as his efforts with Bill Clinton and Bono.
Steve borrowed the mouse (NASA), GUI, ethernet from Xerox, Unix from Bell Labs & FCP. Bill borrowed DOS, Excel and who knows what else.
They both live in humongous homes. They both have humongous egos. They both smoked dope together in the old days.
I used to spend a lot of time hanging out with Bill Gates in the "old days." For the record, I never saw him smoke dope. We were sitting around writing software in machine code and you just couldn't do that if you had been smoking pot.
Also, Bill didn't "borrow" DOS, he bought it (cheap) from a programmer in Seattle when IBM came to him looking for an OS for their new IBM-PC.
One of Steve Jobs first gigs was as a mime in an amusement park. I don't like mimes! :)
The world is too complex to say that the world would or wouldn't have been significantly different if Bill Gates hadn't been around.
It's easier and safer to talk about what his #1 contribution was.
In my mind, it was the bundling of everything a computer user would need in one package. Before that, when building a new machine we had to fill a large shopping cart with OS, screen saver, media player, disk utilities, and all the other stuff that we take for granted today.
Of course the Eurocrats in Brussels are busy trying to undo this, but I don't think they will be successful.
OK, just a reminder, it was IBM that made PC a home name. The simple fact is IBM packaged the software together and supported the product. There was a far superior OS called "MDOS"(can't remember actual name) completeing with Gates "DOS", but when IBM team show up out in CA, the owner was too busy sailing, he thought IBM would wait and paid him more because the world loved "MDOS". IBM team was not impress, even thou they thought Gates' "DOS" sucked, Gates always responsed to their inquiries immediately and in person if possible. The team did not think the IBM PC would be a big "retail" hit, and they had time to refocus they OS wish list over the next two years. IBM marketing was a little too successiveful. But Tandy Electronics had been helping any, thru their Radio Shack stores they been offering homes computers, completing with Apple in real sells. Alot of other brands were helping the home pc image as well. IBM did not want a low end pc that would cut into the very profitable small business market that IBM had(software/hardware), so their choose a weak cpu from Intel, and so-so OS for the PC package. Image if they chose a true 16bit cpu(there were true 16bit micro cpus in the 1975) and real OS with gaming graphics as the first offering. Of course, cost be higher to produce and user software questions would be more demanding for IBM support, but after the dust settle, bye,bye Apple, bye, Gates,bye small pc manufacturers.
DrDOS, CPM-based, multi-taking, much more stable than QDOS, the previous name to the subsequently-Gates-purchased product ($1mil) and re-named to MSDOS.
QDOS, which was designed to be a FAT-based floppy-only OS, litterally took its name from (I kid you not) "Quick and Dirtly Operating System" that was written like most software was back then, by one guy quickly filling a small need in an untidy fashion. Prior to that, Gates and his 5 staff had written a piss-poor operating system for Tandy, calling it TRS-DOS. All of us suckers on TRS-1s called it TRASH-DOS for good reason, not the least of which was the IO to home tape recorders. ONLY. Upgrades finally came out to write to floppies, but it was highly recommended that the data also be written to tape "as an essential backup." Hmmmm, kinda like tape-vs-disk in the camera world today... but I digress.
DrDOS owner was hesitant to sell the op system to IBM because it would have put all his eggs in one basket, and he realized that IBM could simply dump him overnight. At the time, he made what appeared to be a very well-thought-out and "safe" Harvard-Business-School management decision. IBM had a history of eating small companies.
The difference between demise of a superior PC op system and the rise of a poor one rests in the courage/guts/gall exhibited by BIll "Napolean" Gates. The man took on, and subsequently beat, the world's largest and premier computer company - IBM. Bill vs Goliath. THAT was his major accomplishment. As with all war-like endeavors, the rest natrually fell into place of winner-takes-all, with the talent quietly moving to the side of the winner. Quality does not have to be a major factor in the win. Good-enough is always good-enough.
Bill made #3 for "mixing maths and money to build microsoft," just behind Tim Berners-Lee, the father of the web (the story of the first web site, put online 6 August 1991, www.info.cern.ch is in the article above, this site is still active).