I am an outsider, but maybe Luke's audience is looking for wedding rings, a new car, a new house, and maybe they go out to restaurants.
I could buy that if there had been a major shake-up in advertisers during this time but there doesn't appear to have been. I've only caught TBTL a few times but, when I've listened, it appears to be pretty much the same advertisers as they had before - with the exception of AT&T Mobile which is new. Other than that it's a bunch of PSAs and ads for erectile dysfunction.
And despite that their target is 18-34, they seem to be hitting a lot older, based on the listeners who've called in the few times they've taken calls. (Being in the 18-34 demographic myself I just don't find anything at all appealing about Luke's NPR-esque, PG-rated version of BJ Shea. And it's also a bit off-putting when he trashes other air talent in Seattle ... except KUOW air staff, which he fawns over ... just doesn't seem very professional, and rather makes him seem like a 12 year old in a 40 year old's body.)
Honestly, I think Luke's demeanor and style would be fairly well suited to TV; hosting on G4 or something like that. He doesn't really have the looks for TV but the delivery style might come across better because I think, if he had the opportunity to do a few takes and not have to "hit it" on the first try every time, and have a producer who could give directions and guidance instead of just laughing maniacally, he could actually be quite entertaining. I probably wouldn't watch him but I think there would be those who might, certainly at least more than 2.2, anyway.