I'm libertarian with blue tribe sympathies. Whenever I try listening to NPR, I literally fall asleep. It's just something about the combination of cadence, intonation, and premium mediocre presentation of ideas that just paralyzes me. I'm powerless to stop it. Meanwhile I can listen to reactionary [0] talk radio just fine, and sometimes do just for cringe entertainment value. The bellowing of indignant righteousness is stimulating regardless of whether one agrees with the ideas. I don't know that this explains the overall popularity per se, but take it as one data point.
[0] it's a grave mistake to refer to the current Republican party as conservatives. If anything, actual conservatism these days means supporting the Democratic party - respect for American institutions, the rule of law, strong foreign policy, gradual change, etc. The Democrats are even checking the box of fiscal conservatism compared with the past two decades of ZIRP.
I think all the yelling, fear mongering, hate for "the other" on the MAGA based shows just hits your brain different, they will push your buttons whether you enjoy it or it makes you angry at the ignorance, and that can be enjoyable in odd ways. NPR tries to be more reserved and academic, you won't find the cussin' and spittin' that you find on AM talk radio.
Every party has its more anarchistic advocacy points and I can't say when the scales tipped in the abstract. But for my own judgement it was when the longstanding issue of police escaping the rule of law finally got attention, and then the Republican party staked out its position in support of the lawlessness.
[0] it's a grave mistake to refer to the current Republican party as conservatives. If anything, actual conservatism these days means supporting the Democratic party - respect for American institutions, the rule of law, strong foreign policy, gradual change, etc. The Democrats are even checking the box of fiscal conservatism compared with the past two decades of ZIRP.