I like Super User, often I have only to write the title of my question on the "Ask Question" page and the answer shows up in the "Related Questions"
Thus I want to keep it great.
That's great. That's the attitude that makes these sites great.
Computer hardware questions is always getting outdated and doubly so when price is discussed.
I don't think that price should be discussed on SU, as that is too localized for an international audience these sites have.
This question got closed as a dupe, but I agree with one of the comments that a dupe from six moths ago is not relevant from a computer-hardware/price question today.
I think that Is it still cheaper to build your own PC? is a bit more generic. In the last 15 years Roalt's and TheTXI's answers it has been true, and it is likely to continue to be true for some time (IMHO). Also, it's a community wiki question, so anybody can jump in and update it anytime.
In my opinion it should probably have been allowed or perhaps closed as To Localized instead.
I'd have closed as too localized the original, the second one is a tad more generic.
But here is my main question:
What should we do about old hardware questions? A search about best/$ Frobnac is bound to be irrelevant afer six months (or even earlier)
Then close as no longer relevant in six months, update it if you have the edit powers, or/and ask it again pointing to the outdated question, letting the community decide the appropriate course of action.