At the time that Apple started allowing clones, the common wisdom was that this was the Right Thing. We all knew that the PC platform had only succeeded because IBM opened it up to clones, and the result basically forced them to innovate. When Steve shut down the Mac clones, everyone "knew" he'd made a mistake, because it meant Apple would continue to have 100% of a very small pie instead of 10% or 20% of a pie a thousand times bigger. Of course, we all underestimated the effect on quality of all these semi-compatibles. Just read Raymond Chen's blog to see the pain Microsoft has to endure to support ten zillion slightly different pieces of hardware. Steve avoided all that, with the result that his pie is now a whole lot bigger, and his company still owns all of it.
Hindsight: he had it in advance. The rest of us didn't. That's why he died rich, I guess.
>the PC platform had only succeeded because IBM opened it up to clones
That's a little misleading. More accurate to say IBM didn't consider the personal computer strategically important and consequently did not bother to erect barriers to competition, particularly, did not buy MSDOS outright or take other measures to prevent MS's licensing it to competitors.
Elaboration would be welcome. I always thought they wanted to get rid of the plug-compatible manufacturers but couldn't because of anti-trust litigation and because software copyright was much less vigorously enforced by the courts than it came to be in the early 1980s.
Note that after they realized the importance of the PC,
IBM did try to exclude competitors by pushing their own OS and making sure Microchannel and other parts of PS/2 were heavily patented.
The System 360 was basically the first computer to implement a concept of software and hardware compatibility. It was completely spec-driven, which allowed hardware and software to be created and sold by third-parties.
You're right that IBM was bitten by not taking the PC revolution seriously, but even so they never had pure MCA product line at any point, so their attempt to (re-) corner a segment was somewhat half-hearted. They did license MCA to third-parties, though, which is something you didn't see in the pre-System360 era. You could get a Hayes modem in either ISA or MCA (and later PCI) versions. They cost a bit more, but depending on who you talk to it was indeed a better performer, the Betamax to PCI's VHS.
>the PC platform had only succeeded because IBM opened it up to clones
It didn't, the team behind Project Chess used off-the-shelf parts to cut down on costs and dev times so the end product was also easier to reverse engineer.
A company did just that and made a BIOS that didn't infringe on IBM patents. Couple that with an Intel processor and a DOS copy you could buy fair and square from Microsoft and you got a Clone just as good as an official IBM PC.
On Mac clones, it wasn't a bad idea, just too little too late: by the time Apple decided to go ahead with OEMs the Mac's marketshare was a shadow of its former self and Apple was already in trouble. Windows had become the standard, nuff said.
Yep, I'm more or less speaking from the viewpoint of the time. The received wisdom was that it was IBM's deliberate decision to allow clones that made the difference; nowadays we can see that this was only part of the story, but that original belief coloured how people saw things.
On the other hand, though, perhaps the decision to use off-the-shelf parts was also part of the wider clone-friendly decision process. So it's not an either/or, even in hindsight.
IBM didn't want clones, it created the PS/2 to make a PC that couldn't be reverse engineered and cloned by the competition, but even then it was too late.
If IBM could they would have banned all clones, but as I said before OEMs weren't infringing any patents so they couldn't be sued nor stopped.
That was a considerable number of years after the PC rewrote the personal computer market. I don't think the PS/2 was on their radar when they did what they did with the first PC.
Hindsight: he had it in advance. The rest of us didn't. That's why he died rich, I guess.