I'd also like to escape from the Mac, but not because it's expensive. The MBP is ridiculously well made, and the high-end models ship with components that should perform well for 3 years or so. Beyond that point, I'd be looking for a generational change (e.g. CPU architecture, RAM frequency, storage interconnect, etc.) which is more about my weakness for new stuff than actual obsolescence.
Yes, that should be the reason for purchasing a new computer. But that doesn't mean that components should be failing in that amount of time. My first logic board issue happened just outside the 1 year window in 2008, but this was an Nvidia issue... So can't blame Apple right? I would say that the logic board design was horrible regardless of the issues with the chip solder, based on my experiences even with the replacement I got from the recall in 2010. I agree with you on paying for high quality, but well made should include not breaking down.
Also, these days the reasons for upgrading that you mention are diminishing. We all know the limits of Moore's law were being reached, and I was able to upgrade my MBP to 6 GB of memory (Apple's weird limitations on it causing 8 GB not to work?) and put an SSD in it for a solid computing experience sans the other issues.
You're totally right to complain about hardware failures and component deficiencies. Maybe I am just lucky in this regard.
Of course, I've just noticed that there is an option for a 1TB PCIe drive (compared to the 750GB SATA SSD I have now). If I could double my RAM to 32GB as well then I wouldn't hesitate to upgrade. As it is, I'll still probably end up going for it before too long, unless an alternative presents itself.