Teens were welcome in the KRLA lobby, where they could watch the dj's work. When I was a very young teen - actually a 12 year old teenybopper, the KRLA program director was a guy named Jim Washburne. He installed a format clock like the one shown in the video above. It was clearly visible through the big glass window from the lobby into the dj booth. So, the clock was not an exclusive idea of Drake's. ( Sadly, Jim Washburne was later killed in an accident in San Francisco, where he moved to work at KYA).
So, the biggest 50,000 watt Top 40 stations each had their own sound. KFWB was first on the air, maybe in 1957, with program director Chuck Blore. ( I think he learned programming from a guy in Texas named Gordon McClendon? ) They were "Color Radio 98".
Then KRLA started in 1959. The changed from country music format and call letters KXLA. They hired in dj's from different markets who were very young and very fast paced. It's a distinctive very warm, very rapid delivery, very personable sound that appealed to teens.
Afterwards, KHJ and the Drake format started in about 1965 in order to compete with KRLA. ( KHJ formerly had an MOR format, IIRC). I was still pretty young at this time, but I loved rock music and was fascinated with how to run a radio station and create an envisronment with a distinct personality. - D.
P.S. I was fascinated, but not "obsessed". I loved music as a teen, as many teens do. I thought the jocks were really fun personalities and it would be such a fun job. - D.