The PS3 has only been on the market for three years and about two months. So no one can say they've had one running for four years.
The problem with a lot of consoles is that they don't come with special care instructions like vacuuming vents, constant dusting, etc. They're a lot more complex than the consoles that had no moving parts (cartridge based, no internal fans). And with the increase in power and larger cooling systems than were present in PCs just a generation ago, it's no surprise there have been plenty of hardware failures, both from user neglect and inadequate design.
And sometimes it doesn't matter how much you baby your equipment; it can still fail from normal use, even if it's because you chose to play for several hours on a hot summer day (which is far from unreasonable).
On a side note: the reflow technique worked fine on the bricked 40GB SKU. Took the better part of the weekend to learn how to do the tear down and repair job (plus a trip to Home Depot for another heat gun), but it was worth it. It now runs so quiet in idle that I can't hear it over the little fans in my laptop.
Currently backing up and saving the data on the drive, and will have to check with my bro in law to see if he wants to swap it in for a Slim while it's working or keep using it. I'm actually kind of curious to see how long the repair job lasts.
I'm considering picking up a broken PS3 or two on Ebay to see if I can get those working as well.