Excellent point. Horsepower's always been the glamor number, and that's why the Japanese did what was within their means to make it look good. Detroit's underpromise/overdeliver idea seems to be set firmly in the 1960s, where some of the horsepower ratings seemed to be pulled out of a hat. Underrated horsepower = lower insurance premiums and a sleeper quality that car buyers will love, right? No, it's just Detroit's putting too much faith in the average consumer. But hey, a little outdated thinking might actually help them for once this time.
This is the car market, for Christ's sake. NO ONE is trying to be noble here.