The cloners e.g. Power Computing in particular weren't interested in the Mac platform at all. They were simply interested in making money. And the easiest way to do this was to target existing Mac prosumers which were the most profitable segment.
Which meant the overall Mac market didn't increase at all which was the whole point of the clones.
Hindsight: he had it in advance. The rest of us didn't. That's why he died rich, I guess.
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.
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.
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.
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.
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.
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.
Power Computing wanted to expand the market. They built prototypes that went beyond just putting Apple designs in a new case, and showed them at trade shows, and publicly begged Apple to let them sell them.
(IMO, this indicates Apple was never serious about clones; and wanted to keep it on a small scale. It was only done to appease the conventional wisdom on wall street.)