Almost all of my co-workers with PC's have suffered fan failures, power supply failures, etc etc and gone through at least one replacement cycle in that time.
On the flip side, I've had:
2000 Mac Pro - drive failure, power supply failure (and Apple wanted $400 for the replacement supply)
2001 iMac - CD-ROM failure
2004 iBook - 2x power supply failures
2008 MacBook - power supply failure, and a PMU firmware issue that Apple denied yet quietly fixed a few weeks later
In contrast, over the last 20 years I've owned seven PCs, five of which I built myself. One drive failure, one power supply failure, and no other issues to speak of.