People will buy them because it makes it easier for them.

Some dealers like Jennings Chevrolet in Glenview, IL already put 20's on trucks, not sure of the brands.

 

Moritz here in Fort Worth where i bought my truck puts 16-22" wheels on trucks depending on the packages they have and what-not, some look sweet and some look like ****. i saw a reg cab black 03 chevy a while back with black 18" wheels and side exhaust with a 5.3 and a4 that was a "SPORT" package....looked damn good....full black front end. it was sweet.