“You’d be in jail.” — one of the most epic lines in the history of American politics.
That's debatable, no pun intended. Clinton ran a terrible campaign and was such an unlikable person that Trump likely would have won without the debates.
But that was then, this is now. It's easy to say what you will do without an electoral history behind you. Now Trump has Covid, a crashed economy, healthcare, unemployment, issues overseas, and a whole host of other issues he will get questioned on. It will be a completely unfriendly cast of moderators who will do their best to make him say something they can make headlines around. It will be like all his recent TV interviews on steroids. He has nothing to be gained and a lot to lose.