Rightwing and liberal personalities are different.
The right likes repetition and outrage.
The left likes analysis and multiple opinions. That’s not compatible with Limbaugh-style partisan talk radio.
BUT. There are liberal alternatives: comedy and podcasts. Late night shows or shows like John Oliver or Hassan Minhaj’s show use humor to transmit info.
And podcasts explore many sides of an issue and are the new form of liberal radio.