Incompetence is definitely a factor but not nearly as bad as the corruption coming from the top. When you have billionaires lavishing the president with money and gifts in exchange for favors how can that be anything but corruption.

Is this Hanlon's razor? I would argue that it's not that they don't know, it's that they don't care, but it's still fucked up either way.

Perhaps you could define what you mean by widespread? It's pretty clear to me that corruption is present in every level of US government.

The supreme court decided that getting money in exchange for services rendered is OK, and that influence peddling is fine.

The court case that decided this was an asshat that gave a government contract to a company, went to that company and asked for money in exchange, and they gave it to him and the facts of that wasn't disputed. The US supreme court said that's fine, so now a bunch of people are getting their corruption cases re-opened because the US supreme court didn't think it should be illegal.

In addition the supreme court also said companies can give money to a senator after they've won an election (to "pay off debt") which is just a way for people to buy influence.

The citizens united case made it so that companies can just buy influence. You can't however, since for normal people there's a limit to how much you can spend, but companies can just spend as much as they fucking want.

The US is incredibly corrupt, and it's in the open.

Everything is for sale, and the executive branch is running a literal protection racket to business, favours and bribes for government actions, selling pardons, and so much else.