The law of supply and demand states the more of something that exists, the less valuable each individual iteration of it will be. Grains of sand on a beach are worthless. Cans of soup are cheap but still cost something. Limited edition prints are expensive. One of a kind paintings are priceless.
The same is true of commercials. The more ads broadcasters air per break, and the more breaks they air per hour, the less ROI you as the sponsor will see from placing your spot. Simple reason being, the more commercials a listener hears in total, the more he will disengage, zone out, and/or tune away, lowering the effectiveness of your ad. And then, when you accordingly balk at what the station is charging for that low ROI and push for a price reduction to reflect it, the station has no choice but to agree, and predictably tries to make up for that lost revenue by adding one more :30 to its hourly queue. Repeat this ad infinitum. It's a vicious cycle that's been going on for decades. Network TV, for example, started with hour-length shows that ran around 57-58 minutes in the early '50s. Now you're lucky if an hour-length network show cracks the 40 minute mark because of the 20+ minutes of garbage advertising each one is packed with.
The only way out of this quicksand is to make each :30 commercial slot valuable again by eliminating most of its competition. I.e., return to having just a handful of spots per hour and to charging lots of money for each of those handful. The ROI each sponsor sees once listeners learn to stop knee-jerk reaching for the tuner knob each time a commercial break starts will justify the increased cost. In the old days, commercials got results because each spot could sometimes be the only one in its break. You as the sponsor literally had a captive audience -- and your message was internalized and got remembered. When ten different sponsors are all shouting at a listener in the space of five minutes, the listener can't help but tune them all out for his own sanity's sake.
Of course, there's one catch. For this reversion to 1950s style commercial loads to work, the entire industry would have to start doing it together as a whole, all at once, and then sustain the practice long enough for listeners to come out of their shells. Knee-jerk reactions are muscle memory; they take time to fade once the causative stimuli ends. If just station X goes back to 1950s commercial loads, its listeners will still knee-jerk tune away from it when breaks begin simply because all the other broadcasters will be keeping them in a hyper-sensitized state with their still-intolerable, 2020s commercial loads.
Considering the financial straits linear television and radio are in today, I don't know if the industry as a whole would even be willing to try this though. They are hanging on by their fingernails already and since a transition like this would require loss-leading for a while (as people learned to come out of their shells), that might just be enough to send a lot of the participants into bankruptcy. There's something not unlike an end-stage narcotics addiction about all this with them. They're all injecting so much, it's killing them, but they're also so addicted, the stress of the withdrawal from cutting back might kill them even faster.