Elon going to prison would not stop Starship. Neither would it stop if he died.
And in some absurd crazy scenario NASA could basically 'take' it because its relevant for future mission. NASA has done so before if a company they needed went bankrupt.
SLS depends on a incredibly long list of suppliers. Far longer then Starship.
There is a real non-zero risk of something bad gappebing to him and then future of SpaceX is in question, its not a robust institution like NASA