Yes, agree. He was a big radio personality, that came through the speakers, and I've heard from a few others that he was a decent guy, not full of himself. Too bad he went straight, but he deserves a life, and the disintegrating state of radio seems to have made that increasingly difficult in the last couple of decades.
I wish I could find it---it may be in the posts the board lost years ago, but John participated here back in the 2000s.
In one of those posts, John told the story of his departure from KFRC. Basically, he did let ego get to him once and lived to regret it. In 1979, he and everyone else at KFRC was making $37,000 a year, apart from Dr. Don Rose, who reportedly was at $300,000.
John went to Les Garland (the PD) and demanded a raise. Les told him he was right, that he was an important part of the station's success, went to the GM and came back with an offer of $60,000 a year (that's $246,000 adjusted for inflation). John told Les that was an insult. Les went back to the GM, they both went to RKO and they came back to John with an offer for $90,000 a year ($369k adjusted).
John told them to stick it and walked out. No radio gig. He went to work for the Dale Carnegie ("How To Win Friends And Influence People") organization---an irony that wasn't lost on him later on.
Things got worse. John says Carnegie reneged on the agreement and never paid him. John worked for KCBS-FM and its successor KRQR, but was little more than a time and temp album jock--at one point relegated to overnights. He got back to afternoon drive and CHR at KWSS in Gilroy/San Jose, and that got him back into SF, at KIOI, KSFO/KYA-FM and even at KFRC in its oldies incarnation---but that was when the industry was playing corporate musical chairs with talent. This is a pretty good summation:
KFRC's John Mack Flanagan: The BARD Interview (Summer 1992) | Bay
Eventually, John took a gig as a security guard/greeter at Embarcadero Plaza---the same building where he'd worked at KCBS-FM and KRQR.
In the late 2000s, he got lured back to KFRC's re-birth on 106.9 with a Sunday Beatles show---and got let go with everyone else when the station flipped to a simulcast of KCBS a few months later.
I corresponded with John for a bit from there until his death in 2018. A good guy who deserved a lot better from the business he loved.