Back before the communications act of 1996 there was a limit on how many radio and tv stations a company could own in a market. There were still many locally owned and managed radio stations at that point.
After the act, the big companies started a radio station buying frenzy that had many stations bought and sold several times over a short time span. Each sale drove up the debt held on that station and required those stations to run formats that were uber commercial just to keep up with that newly acquired debt.
DJ's weren't allowed to say much anymore, if in fact there were still DJ's at the stations. Commericals started taking up more and more minutes in the hour. And playlists were culled to 100 or 200 songs. Great songs perhaps but they didn't play many of them.
So you ended up with stations that had a very bland presentation, no local connection, and a ton of commercials. This is not a recipe for long term success.
When I was a kid radio was pretty entertaining. Lots of great memories listening to some great stations with very talented DJ's.