Let's not overstate what Jobs did.
The original iMac merely packaged relatively dated hardware, and an incredibly dated co-operative multitasking OS, into a cool case. Apple, even at that point, still had a 'cool brand factor' so Jobs, for the first time, really leveraged that. The iMac was cool enough to become an iconic consumer products but market share barely shifted overall. Still, it stopped the rot, and the drift away from Apple in the pro markets was halted.
Next came a lot of rubbish in amongst the good stuff to be honest. A toilet seat laptop? A cube that had less spec than a tower but cost more. The same basic iMac design in lots of colour, including flower power. The iApps were a good move, though, making an iMac a much more complete experience out of the box than a typical PC.
Then came the move that Steve Jobs' return was all about - taking neXt's OS, rather than an in-house solution or BeOS, updating it, and rebranding it Mac OS X. Soon Apple went from having an 80s-era OS to the most advanced on the planet.
Right away all-new pro-apps like Maya came on board, Final Cut, now on a tougher OS, made huge progress. The move to Intel opened up Xeon workstations. Xserve was a great enterprise server. There was even rumour of Apple looking to buy commercial unix vendors to get into the enterprise.
But then the iPod came about. Initially a Mac-only refined mp3 player it, of course, went crazy. Then iTunes launched and Apple had an easy-money machine on their hands.
But Jobs' final errors were forgetting that consumers, while a massive market, are fickle and to a large extent throwing the loyal pro market in the trash. Many a small fashion brand has become flavour of the month, expanded like crazy, then struggled as next year's thing takes over. iPhone was the cool thing for several years, but now it's phablets, next year it'll be some other shiny thing.