As the owner of a Compaq I can relate to both sides.
They are designed for the mass market. The majority of computer users do just that: they 'use' the product. *Some* of us (huge minority) tweek for added performance. Compaq evidently built for stability & doesn't want us 'tweeking'. If Intel didn't change to FC-PGA, FC-PGA2, 423 & 478 pin CPU's > we could upgrade our 'closet' machines. That wasn't Compaq's doing. Memory changes weren't either.
For Ref, me & others: it is a pain, but I realize we are the minority. For us there are software programs like CPUCool, thank goodness. There is also excellent sites like this to find (hopefully safe) tweeks. Are we going to get the large gains like the 'programmable' components allow > prolly not. Can we find gains anyway, yes: it just requires different tactics. More, not less, literacy. :grinthumb
I do blame Compaq & other mfg's for not having adapters available to upgrade, but I do realize that is a niche market & mfgs. are in it for their stockholder$.
We 'tweekers' really don't matter to them. I can say mine has been very stable & reliable. Blue screen of death is unknown to me, TG! As long as I only 'tweek' 3rd party components, I'm fine.
It's not like this is a 50yr old industry & things don't change on a daily basis either.
Just a little perspective from my edge of the coin,