I'm 25, listened to rock radio for the past 15 years and have regularly heard STP on the radio since then. Live in NC, and currently our new rock/rock alt stations that I hear are 100.3, 106.5 and 93.3. All play at least a couple of STP songs daily. The most played ones are Big Empty, Wicked Garden, Interstate Love Song, Vasoline, both versions of Plush and Sex Type Thing. Those are the most played in no specific order. In the past 6 months I have however heard all of the following: both versions of Plush, Interstate Love Song, Sour Girl, Trippin, Down, Unglued, Vasoline, Big Empty, Sex Type Thing, Wicked Garden, Dead and Bloated, Big Bang Baby, Lady Picture Show, Days of the Week, the Dancing Days cover and All in the Suit that you Wear (Revolution and Break on Through were both played when they were new but didn't stick long-term). Heard Barbarella once on the radio when 12BB came out, heard Talk Show's "Hello" once, heard Goodbye from AoA a lot when it came out (it has however disappeared) and heard "Father Figure" once. These guys have always gotten tons of radio play where I have lived- not so much on their side projects- except VR (the first album got tons of play, and a little from the 2nd album and the soundtrack singles). I listen to the radio when I'm in the car, between 15-30 on an average day. Either you guys haven't listened to the radio for that long (by that I mean, not very many years) or you just recently became STP fans and only now notice. Plus, maybe you're rock stations suck. Mine do for the most part, however STP, Alice, Pumpkins, RHCP, Pearl Jam, Nirvana and Soundgarden have always been staples, regardless of the change in times and changes in music.
-Steven