I'm no engineer, but I have some of the mindset. in fact I often characterize myself (or more precisely my mindset) as an orphan having been raised by an engineer and an empath.
That said, I have had my share of experiences with computer hardware and PSU failures. PSU failures are (outside of fire breaking out in the server room) the worst thing that can happen to a computer - partially because spares can be hard to come by, but mostly because a PSU failure may lead to other parts failing as well (most probably power spikes). I've once had a PSU fail on me in such a way, that not a single component (CPU, RAM, MoBo, drives, PCI cards) was salvageable. I sincerely hope this is not the OP's case...
But, to get to the issue, and I do not expect y'all to agree, I am of the opinion, that no computer component which does not have moving parts SHOULD be able to break. That they frequently do so is, IMHO, attributable to a combination of design flaws or component QA issues.
I think the QA-aspect does not necessitate elaboration, on the other hand what I define as a design flaw implies an (IMO) skewed prioritization between power (capability), price and durability.
What I mean is that (and I think anyone with 10+ years working with computers can relate to) the whole concept of the lifespan of computer hardware being 3-5 years is absurd. We worked with that (then) state-of-the-art hardware in 1993 or 2003 and while we don't expect (or maybe "should not expect") it to run 1080p video, we should be able to expect it to do the same tasks today as it did back then.
Fact is, there are a lot of people who would be well served by 10-year old hardware, and I'm not thinking about sub-saharan Africa here. My personal everyday computing environment is based on machines from 2011, 2008, 2003, 2002 and 2001 (first two and fourth mentioned in sig), I've outfitted a number of modest computer users (with needs ranging from word processing via light DTP to web design) with

-hardware from 1998 through 2008 (mainly 2003-2006). One of the central reasons why I've transitioned back to apple-hardware is that I've found the hardware to be more durable, but I'm starting to worry...
Notwithstanding physical wear and tear (and knocks) and components with moving parts (HDD, opticals, fans and hinges), I think there is no reason why machines could not be designed to reliably function for 10+ years.
In fact I just resurrected my old Sinclair (anno 1982) and it still works...
I acknowledge that the computer business -model is largely based on designed (forced) obsolescence, but I seriously question the sensibility of it - not only from an environmental standpoint.
RGDS,