That is again due to how they are treated and funding constriction. NASA has not received the same "grace" in failures that you are giving SpaceX. They'd love to do more missions and they're also better about doing things right. You should know whether your rocket works before it's launched just like a bridge needs to work as built. NASA also doesn't get money from it's missions. Whatever they put in orbit doesn't generate revenue it is only for public data gathering.
That is such a crass reference to Challenger... SpaceX mishaps so far have not killed people. Will you still be giving them leeway when they do?
Republicans didn't even want him running now in 2024, but his cult are fanatics and enough of them that unless they start unified behind an alternate candidate he'll keep being where he is. During the R primaries this fact was talked about a lot. All the other candidates together had enough to beat him but none of them were willing to be behind another candidate. All the losers endorsing Trump instead of others really didn't help.