The SpaceX IPO prospectus states that the company is targeting a TAM of $28.5T, equal to roughly a quarter of the world's gross economic output.

Patrick Boyle said it best. Roughly 1 billion people on the planet make more than $12k annually (folks with "discretionary" income). Divide that TAM of $28.5T by 1B and the every single person needs to give SpaceX ~$28.5K every year forever in order for that figure to make sense. It's more than 3x what the planet spends on food currently.