But I see a lot of that announcement, and the others someone else pointed to as his "aspirational, but ultimately never going to happen" goals - whether he believes the claims are achievable, or not, he says these things to energise people to working/paying for him to try
It costs him little to nothing to say, and other people's time, effort, and capital to try (and succeed/fail)
Tesla is falling to pieces now, and SpaceX is getting loaded up with completely unrelated projects (xAI) in order to try and make it look saleable (I guess) - it's very difficult to see the Mars announcement as anything but hype.