I got nine straight years out of my Mac SE/30, five from my (used) PowerBook G3 Lombard and five from my iBook G4. Also my second generation iPod works fine (aside from a dead battery which was mostly my fault) and my 4th(?)-gen iPod is in ship-shape. In fact, every Apple product I own aside from a refurb Airport Express will work if you plug it in -- that's two IIe's, a IIc, two SE/30's, a Quadra 840AV, a Lombard, a Pismo, two iBook G4's, an iMac G4, the aforementioned iPods, an Airport Extreme, an iPhone 3G, a unibody MacBook, and a MacBook Pro.
In my 21 years of Mac usage, I simply do not share your experience.
I agree that Macs will physically last longer than just about any other brand out there (other than the old IBMs), but the question I think is why you would want to keep a machine that long, and what good it will be if you do.
I had a 15" old-gen MacBook Pro. Ran like a dream, and physically much sturdier than just about any of the plastic crap out there. I had it for 2.5y before what I wanted to do outstripped what it was capable of offering and I switched to a unibody MacBook Pro.
That's what the previous poster is getting at. Yes, the Mac will remain functional for a long time, but what's the point?
Do you really need all that processing power or do you merely think you do?
I do just fine with a 2GHZ Core 2 Duo (1MB L2) desktop PC with 1GB RAM (I've even used it to run Windows Vista in VMWare on Ubuntu). Heck, you wouldn't notice the difference between my PC and my 1 year old MacBook with 2GB RAM and a 2.4GHZ Core 2 Duo (2MB L2), mostly because I keep my Ubuntu install in very good shape. If I was using Debian, Arch or Slackware, I could get even more performance out of this baby.
It's likely that I will not be upgrading this PC for a few more years. Thanks to cheap, low-end netbooks, operating systems are getting lighter. I expect this trend will continue for some time, and I intend to take full advantage of it, partly because I don't want to waste perfectly good electronics, but mostly because I want to see how long I can keep them running :p
Computers never get old. They just become incompatible with the state-of-the-art.
I've never owned an Apple product before last year, so I'm not making any comment about their durability, one way or another.
My point is this: go and survey today's Apple users, and ask them what they like about the products, or why they decided to buy. I'm willing to bet that "durability" will not be in the top three reasons.
Apple is one of the very few tech companies who has managed to meld its products into a fashion item, and over the last few years (since the first iPod, really), that is what made them as successful as they are today, NOT durability.
This also means that people want to replace their Apple products with shinier, newer models, long before they actually stop working.
I can't comment on BMW bikes, but I think the same is true of BMW cars - how many people buy a brand new BMW with the intention of driving it for 20 years?
In my 21 years of Mac usage, I simply do not share your experience.