Knowing your limits may be part of the picture. I would say that back-stabbing the most popular political figure in history after same political figure gets you elected is probably the #1 reason this guy is tanking. He’s a snake.
I expect them to fight hard to try and get the nomination. That’s how it works, even if they aren’t necessarily fair.
However, I can forgive DeSantis if he gets behind Trump if Trump gets the nomination. You fight like hard for the nomination and get behind the nominee once somebody becomes one. If DeSantis does that, it will all be water under the bridge for me.