Here come the haters.
Howard spent most of his career not making much money, yet he continued to do it for decades. When Carson was making millions, Stern was making peanuts. Did he respond by selling himself out? No, he just kept doing radio. He made a movie that he knew wasn't going to make him wealthy. He made some money on a couple of books, but these are all things he did because he wanted to, not to make money. If he did these things to make money, he would've kept cranking out books and movies.
He's had his show (HSS) on TV, and let it go. He probably could've kept it going if money was the thing, but it wasn't. He did AGT because he really liked the show, and also because he wanted visibility on TV. He's become a top name in entertainment; therefore, he won't accept being paid less than the other judges. Likewise, he won't carry SiriusXM and not get paid appropriately, it's a matter of respect. Look at what Limbaugh makes, look at what Leno and Letterman made.
Howard's obsession isn't money, it's fame and respect, but money goes hand-in-hand with those. When he decides to step back from working, it won't be the money he'll miss, but the fame.