The best beers are homemade.
I brew a bit, and I don't know about this. People say my beers compare favorably to commercial samples (most recently, Rockadanny, a Bacwoods Bastard copy tasted against the original). A lot of this, I think, is a freshness effect.
Remember, a lot of the commercial folks were once the best homebrewers. I went to graduate school with Paul Phillippon, and drank his yummy homebrew; now he's the man behind Duck Rabbit, "The Dark Beer Specialists," and brews even yummier commercial beer. (Duck Rabbit is has growing distribution, based in NC, keep an eye out.)
My2c,
John