Apparently, Busy is still a hero in the eyes of some males. Perhaps that's what Kia is going after, especially in Texas. Let's face it, in that great state you risk being called a "wuss" if you don't drive at least a Ford F150. And many folks are probably still watching his brilliant turns in older movies such as the "Buddy Holly Story" along with action pieces that include "Let's Get Harry." Kia was also probably pretty smart in applying the "any attention is good attention" strategy. They pulled in an aging once-well-respected actor whose name is instantly recognizable for whatever reasons. Whether it's abusive behavior or off-the-wall outspokenness from celebrities, advertisers know that simple recognition matters.
Has Gary Busey sold Kias? Don't know. If you decide to buy one, go ahead and follow his directions to tell the sales rep "Gary sent you." If that rep has seen some of his more recent movies, he may be afraid not to give you the best deal.
You'll see these commercials as either a load of fun and go along for the ride or as a poor B-grade showcase for a has-been actor. That's too bad if you think the latter because you certainly don't think he's doing them for free. More power to him.