These decisions are usually made by a semi skilled person called a "component engineer". As long as the specs match, they buy the cheapest parts they can find. Reliability testing is left to the vendor. Modern supply chain practices.
The planning is called "next quarter", not "long term".
Heck, in the long term one will probably have been laid off, so why plan for the future of the corporation?
Had a Dodge Neon with paint problem like your Hyundai - will never buy Dodge or Chrysler again. The result of short term profit planning is lost customer long term forever.
I think that manufacturers count on the general consumer to not know the difference until after the sale (and warranty). I do believe that in time their lack of best practices will catch up, but it may take a long time. Given that, it seems that they will continue to make the poor choice because they won't see the connection between the cheap power supply and future loss of market share. Reminds me of the first time I owned a Hyndai, the paint failed after 2 years and it was not covered under "their" warranty. I got rid of the car and will never buy another one. They lost a future customer for life and all my friends/family as well. Sometimes they just don't get it.
I've also noticed how many of them run at very high temperature. This does not just reduce useful life and even become a potential fire hazard in a badly ventillated environment but the heat is also a sign of wasted energy. Perhaps it's just a couple of watts per unit but for millions of devices, many of them running 24/7, it all adds up.
The next example goes back a few years but it reminds me of the result of a test, comparing set top boxes. One particular box used 28 watts in full operation which reduced to 25 in stand-by mode...
This is one of my pet peeves -- those 75 cent Chinese-made wall warts that usually fail long before the expensive gear they are powering.
I too had a wireless router that had problems with its PS failing due to exploding capacitors. The first time one failed, I bought an exact replacement online, but after 6 months that one failed too. I was tempted to do exactly what you did with a decent quality PS and the plug from the dead unit, but instead I decided it was time to upgrade from G to N, so I just bought a new router...of a different brand.
I wonder if manufacturers realize how much their choice of PS supplier can affect customer loyalty and future business. In my case, I now have the perception that Brand X and Brand Y are both excellent WiFi routers, similarly priced, and with all the features I want, but one of them ships lousy power supplies with its routers, while the other seems to have a higher quality PS.
Guess which brand I am reluctant to try again when it's time to upgrade to a new router?
This morning, as I entered my office, I found the VOIP wireless phone crying for a base connection, that was lost.
Since the base station was just across the small room, I thought of an unnoticed power down in the UPS to which it's attached. Though power was on, so a quick measure made clear the power supply was dead.
Maybe I should have stressed that the cheap power supply has failed.
How comes that so many good quality devices are sold with so low quality power supplies?
That happened today with a nice Siemens Gigaset unit (under UPS, so with a reasonably clean line supply), but I've seen it happening many other times. I can remember a couple of Netgear routers, in two different sites, both with a failing cheap PSU.
Do these large manufacturers know the risks they're facing, choosing a poor supply unit?
Average customer isn't to investigate whether a cheap PSU has failed, or the whole unit is broken: will just rate the product as unreliable, and maybe extend the judgment to the manufacturer ("Products from them? I had one that was broken in a few months of usage!").
With the help of a screwdriver (handled as a chisel, of course) I opened the failing wall wart, revealing the bad smell of a burned cheap CapXon capacitor, glued to a few other components.
A few cents of electronics, that in many cases would have doomed a fine product to the waste bin.
Luckily I had an old supply hanging around, with similar characteristics (just 6.0V instead of 6.5, but up to 700 mA instead of the original 600), so I dissected cable and plug from the dead unit, and built a perfectly working Frankenstein. At least, with higher quality components inside.