Granted, the current Camaro is not as pretty, or as tough-looking as the last generation. The interiors are fine, nothing to write home about. However, its engine choices are sublime. The Mustang keeps sales going with special editions every few years like the GT350, Bullitt or new Mach-1. The Challenger does the same with its Hellcats, Redeyes, Demons and the like. Maybe Camaro buyers are sick of SS and ZR1? Chevy did just start offering the LT1 trim with the good engine for cheap, which makes these numbers even more surprising.
The moral is this: we love living in a world where Camaros, Challengers and Mustangs compete for supremacy every year. If every other domestic vehicle (besides the Corvette) becomes an SUV, we can live with it. Just give us a few two-doors to play with (and argue about).