I don't think I would ever replace Windows PCs for a Mac. Now, I'm not gonna go and bash Apple like some people do...in my life I've only bought one of their products. It was an iPod that I bought 13 years ago...and that thing is still working today exactly like the first day that I bought it.
But for me the problem is that they are just too expensive. Also with computers, it's usually not long until they are out-teched by the newest models in the market. In addition to that, it's the repairing issue that you mentioned. With a PC tower, no matter how ugly it looks, if one thing breaks you can go to any store in the world and buy just that one component and usually replace it yourself even if you are a computer noob. So even though I respect Apple products I think I'll keep on buying 600-700$ PCs that I can just replace after a few years. But of course, my computer needs may be different than someone else's
You are definitely right. With most things that Apple makes you pay a big premium for the Apple name. This is different in that there seems to be very little mark-up but as you say the practicality is a big concern with something like this.