Starship: at least one human must land, successfully and alive, on Mars in a Starship or successor vehicle.
High speed rail: At least one human must travel, successfully, from SF to LA (or the reverse). Tracks must be capable of at least 90mph fo SF-Gilroy and Burbank-Anaheim, and at least 155 mph for the remaining pieces, with the majority of the travel distance exceeding those minimums. (Current plans have speeds below what would normally qualify as HSR for those sections. And obviously the train will slow down for intermediate stops.)
If either program is cancelled, successor programs will be used instead.
I'm generally a SpaceX optimist, and I'd give uncrewed missions launching in 2026 at least 50% odds. But I can't see crewed happening for at least ten years. SpaceX is bold, but they'll want to prove a bunch of things to themselves first (beyond what Elon stated):
Long-term life support (probably via a Starship parked in LEO for > 1 year)
Transfer of propellent from one ship to another while on Mars (for return trip).
Launch from Mars and return to Earth
although writing this really has me wondering if the first trip will be deliberately one way... I've been wondering about Musk's mental health for a while, and it wouldn't surprise me if he chose to suicide by Mars.
Love the question btw. It's a pity margin loans are gone because it's a very long wait before payoff, regardless of which is first.
@DanHomerick When do you think we'll see the HSR link all the way from LA to SF? They're currently saying 2030-2033, and I'd be pretty surprised if there weren't more delays given how things have been going. So that might be a decade+ away as well.