There's at least three reasons he should be in jail.

I'm saying he's not in jail because he used the power of the presidency to shut down the investigation into Russian collusion.

He's also got one of his own judges in the documents case delaying that case for him, so that he can shut it down if he wins the next election.

The election obstruction case is being held up by the supreme court, presumably for the same purpose.

It appears that the federalist society has effectively removed the rule of law in the United States.

But he's also broken state laws, when he set up the fake elector's scheme. Georgia is the only state that has brought charges, and he's playing delaying tactics there too. But that one was always going to come to a head after the election: but the federal DoJ can't directly stop it.