Even if it was left in place it would have become increasingly a joke as non-broadcast news grew in the form of cable rollouts and the internet.
You’re ignoring the power am radio has had on the political landscape.
I don't think this gets mentioned enough. Rush Limbaugh was the result of the doctrine's abolition. You can draw a straight line from Limbaugh to Fox News, et al.
WNYC's "One the Media" have done just this:
"How Rush Limbaugh Paved The Way For Trump" (2021)