I agree with you on this, although, as you say, there was the Mac Pro, I suppose. There was no reasonably priced Mac desktop solution in the period. One of the reasons I stuck with Windows (which I had been using since its inception and MS DOS prior to that and CP/M prior to that etc.) in that period and only moved to a Mac for my laptop (Mac Book Titanium (2002?) which still boots). Once the 24" iMac came out I used that experimentally and moved to the 27" as soon as it was released. Took a while before I completely gave up my Windows machines, but eventually did in 2015 and loved the iMac since then. No longer, as the new M series based 24" is much less useful to me with its small screen and memory restrictions which is why I now have a 64GB memory M4 Pro Mini with 2 27" 5K screens one of which I had with my last 27" iMac in 2020. It is fine and works for me, but I can still see the attraction of a larger all in one.The 27" iMac was an unexpected hit because Apple's other desktop offerings were terrible for most of the 2010s. For users wanting a speedy K-series desktop Intel chip and integrated graphics for a decent-ish price it was the only option. The Mac Mini used clock throttled B-series Intel chips and weak integrated graphics, and the Mac Pro became priced into the stratosphere with Apple's decision to exclusively use Xeon chips. Add in the Mac Mini and Mac Pro languishing for four and six years, respectively, between updates, and demanding users really didn't have a choice but to go with the 27" iMac. The fact that it came with a great display is, of course, icing, but I'm sure it pained plenty of people to have to discard the display when it was time to upgrade.