Actually, I kinda doubt it. I think radio is a lot like landline telephones: it's "dying", but it's taking a long time because there's a bunch of dinosaurs who still use it and won't quit until they're dead. (Disclaimer: I listen to radio in my car sometimes, but only NPR, not anything commercial.)
So basically there's a captive audience here that won't go away any time soon, and is getting older and easier to manipulate into buying stuff. It's not a growth sector for sure, but it is something a company can put minimal investment into and milk for profit. This is seen now with landline phone service: it's gotten really unreliable in many places these days because the infrastructure is decaying and companies are spending the absolute minimum to keep it going, but they're milking it for profit from all the dinosaurs who refuse to give it up.