Recently one of the Chapo hosts was making fun of Biden by pointing out his pitiful net worth in comparison to Mitch McConnell who "needs a bribe of a football field in Saudi Arabia to lift a finger (paraphrased). They put forth the idea that UnClE jOe really is a true believer in all this bullshit. He lives and dies by neoliberal centrism not because of the immense profits but because he's so phenomenally dumb he actually buys into ruling class propaganda while being part of it.
Something to think about anyway.
Politicians are either rich when they get elected (Trump, Edwards, Romney, Gore), get rich afterwards from speaking fees/book deals/corporate sinecures (Clinton, Obama, a ton of B-listers), or marry into money while they're in office (Dole, McConnell, Kerry, McCain, Ryan).
Biden had a government job for 46 years and married a community college professor. He hasn't been shy about paid speaking gigs since then but has only had a couple years of it. Don't think it goes much deeper than that.