I'll have to say, the only good thing about computer manufacturers leaving the install files on the hard drive is that when people bring in their computers to get fixed because they've gotten so much ad-ware and viruses from porn sites and dodgy emails, it's easy for me to just format it for them and charge them a buttload of money. Software repairs on computers has to be one of the largest ripoffs I've ever seen; it's all profit, no work at all if you know what you're doing, and can be done without you even being there.
It doesn't matter how many times you say "Bring all of the CDs the computer came with," or "Bring the Windows Setup Disk," they never do, or they bring just the disk and not the serial number on the sleeve. At least this way with the streamlined version I can just set it and get on to selling other stuff.