Not my real reason, but one of my observations at events the past few years, more and more guys with box stock ARF's getting awards for best this and best that, come on get real a guy who builds a kit has way more time and effort into his model that the guy who buys an arf no matter who the company is who sold it.
I also work at a hobby shop on weekends and last Saturday afternoon was spent with a guy who didn't buy his plane from us. He heard we are a BVM dealer and thought I should spend a lot of shop time fixing his mistakes on his ARF jet. I told him he should have bought a good arf like any of the BVM or recent Skymaster ones and found out he just got into the hobby and has no building knowledge, his response was he just wants to fly not build.
See Jacks Diaz's Arf paradox thread for other issuses with non builders and arfs.