I certainly didn't pay as much attention back then as I do now, but I don't remember stations ever using cold segues, seems there was some element of imaging between every single song, whether that was a jock break, a piece of imaging, or a jingle, and there are still plenty of stations run this way. The question is though, when and why did stations start doing this? They're not as bad as they used to be, but a few years ago, especially at night, my local Hot AC, KPLZ, would play 4 songs in a row with no imaging.