I've spent a year at my new work place. It's a school, so they buy the cheapest of everything. That means we have 4 different brands of servers. Each of our server rooms have a dedicated AC. I had three hard drives go out, a mother board go out, a NIC, and a PSU. That's out of one server room with 6 servers. Keep in mind, they are the cheapest bid. None are more than four years old.
There's another server room we had in an old building, it was in a wood shop. When I found that out everything got moved and replaced. Those servers and switches, to my knowledge, have been up for 8+ years. They had saw dust on them, crazy dusty, and old. Again, the cheapest bid. No idea why those servers, probably in horrible condition for 7.5 of 8 years (or the equivalent), never failed. The fans weren't turning there was so much saw dust.
Moral of the story? They do what they want. Same, cheaply made parts. I would be interested to see what you have come up with in your research though. Good luck!
Oh.. saw that was last month... sorry.