From what I've seen they think its like a 50/50 chance of the first starship blowing up, but they are already building the next couple ones, so they are ready for that. They are not just building one rocket, they are building a rocket assembly line and it seems like they have cracked the code on that. Not a chance one explosion will end spaceX, I'm not sure how you could seriously think that if you have been following the development.