imacs along with Macbooks since changing to Intel processors share probably 90% of the computing hardware as PCs. Apple like adding a few propitiatory touches to this hardware whilst they may improve the hardware slightly they will improve Apple's profit margin. A lot of their products are not very 'green' as they are not readily upgradeable, try upgrading the memory and a lot of the time it will be soldered on.
Most people when comparing Macs to PCs never seem to compare like for like ie a macbook pro up against a £500 Laptop - no contest. The software is a lot better than
Microsofts offering if you can get on with it, personally I can't, but Win 10 might make me take another look.
I remember reading an article many years ago concerning the ipod, under $10 dollars of components around the same again in labour costs, $70 odd of profit to Apple.
As for being indestructible, a relative of mine who uses them for his business has had a couple Macbooks Pro break (repaired under warranty) and his imac died before Christmas at north of a £1000 to fix is now written off . Yes if they survive then they do have good resale value.