I think you're agreeing with me here man. What I meant wasn't that whenever somebody is playing fast, they're doing it cause they want to hide lack of musicianship.
I was saying that many people from the 80s used fast scalar and sweep arpeggio techniques to cover up the lack of much substance in their work. I listen to a lot of fast mofos (Jimmy Bruno, Pat Metheny, Mike Stern, Tal Farlow) but not cause they're fast. They only turn on the juice occassionally, and it's not the kind of thing you'd listen to just to be impressed by speed, because they're not playing fast that often, unlike most shred players who, if they can play fast, will do so for about 50 percent of each of their songs. (That doesn't go for yngwie, he does it for 80 percent, maybe more.)
Sure playing fast and impressive is fun, but if it becomes more of a focus than putting actual musical ideas into your work, as I think it did many (but not all) 80s guitarrists, then there's a problem.