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.
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.