I don't even know if I've turned off my rMBP for more than a few hours in the past 11 months I've owned it.
My G5 usually sleeps as I have storage space and print serving happening. I can send a wake on LAN request to fire her up from my laptop if I'm in another room. My Mac Pro is at my parents house right now but even if it's with me or I'm with it, it says off.
Where do you get these statistics? You do realize over 90% of the worlds computers (desktops, laptops, and net books) run a version of Windows? Nearly all companies rely on Windows computers for their employees and certainly do not replace their computers every 1-2 years. Neither are your average consumers. It depends on the industry, but companies update every 4-5 and replace due to the fact they're obsolete, not broken. A bunch of companies lease too btw. Considering your newest computer is 12 years old how do you come to these conclusions?
Yes because Apple computers are... not... computers...? Right. Oh that must be why they changed their name from Apple Computer to Apple, inc. Complete misnomer for decades. So if you haven't really fixed Macs, how do you know their longevity is that much better?
My anecdotes:
My towns school system replaced their primarily G4 run computer system (i, e, and Power Macs- some G3s were about) completely with HP Pentium 4 Desktops. After 4 years they reported the PCs had less hardware problems, much cheaper repair costs, and the initial cost of the PCs was less.
My parents had a P4 Dell running In the basement of their house as a server from 2002 to 2011 20hrs/day- 6:00AM to 2:00AM. The power supply failed In like a year but other than that zero issues. I expect it still starts today. They also still have a 1996 PII Gateway that was used through ~2003. I fired it up about 2 years ago with no issues. At the time it was only 17 years old