Due to the wonderful and ever improving economy of B.O.
A good part of the problem is that Radio Shack started out for hobby types, the build it themselves and fix it themselves. But now, computers are so complex, one does not replace parts, but rather entire boards.
At my company, we had a tech dept who used to fix our computers. Now we just contract it all out via extended warranties.
There are now far fewer radio/pc hobby types around.
Other than the gamers who mostly just do plug&play.