Rush was an experienced AM radio performer who understood what makes a radio program entertaining.
He had worked at perfecting his craft long before trying to introduce politics in it. And when he did, he still emphasized humor, music, and all of the elements that kept an audience listening.
This is what his imitators lack. They aren’t radio professionals. They are political enthusiasts. They lack Rush’s understanding of how to keep an audience entertained.
Hannity is a prime example of someone having zero understanding of radio. He’s strident, repetitive, he machine guns his listeners with talking points. He’s proof that a lack of talent is no barrier to success.
Until someone comes along who is as good at understanding radio as he is at political commentary there will be no equal to Rush.
But you noticed that the music fell off, and also the Paul Shanklin skits which were hilarious. Maybe Shanklin charged too much. So the show evolved into a daily political discussion with fewer tangents into Apple products and cigars. (which may have contributed to Rush’s health problems.)