A Prusa MK4, completely factory built, is a reliable workhorse for me.
I didn't suggest otherwise, nor was that even part of my point.
Prusa’s primary audience has been people who don’t want to tinker.
I think they just screwed up the design of the MMU but they never went back to the drawing board.
"hot mess" is not a fair assessment. The MMU2 was terribly unreliable, but the MMU3 is OK. It's surely more complicated to set up and requires more space than the AMS, but on the other hand, I think AMS concept is just plain bad. It's incredibly slow and produces a ton of plastic waste.
They still seem to be thinking the primary audience of 3d printers is people who tinker. It's not been that way for a long time. People just want to be able to unbox, plug it in and print. The second you add in the "oh just spend 5 hours tweaking this spaghetti mess of an MMU" you've lost them.