I avoided iMacs altogether until the PPC -> x86 switch because Apple used to provide an entry-level PowerMac tower. That went away with the Mac Pro. Since I'd never had a problem with any of my previous Macs (excepting the iBook I spilled Jack Daniels' all over), it honestly didn't occur to me that I'd need to be cracking the thing open. Since I am no longer a gamer, I don't have much of a need to constantly tweak/upgrade my system.
Of course I always knew an all-in-one wouldn't be serviceable. Until my recent troubles that was always only a theoretical concern (in theory, if something breaks, fixing it will suck)... The iMac was the first (and last) all-in-one desktop I've ever owned. All the disadvantages of a laptop, combined with all of the disadvantages of a desktop. Had Apple sold a reasonably priced desktop machine, I might still be on OS X. .