Some of that sounds like unreasonable optimism.
Given the track record of SpaceX, it's safe to assume that Starship will eventually fly and that the lower stage will eventually be reusable. Getting the Starship itself to survive reentry and landing in good enough condition to fly again without major refurbishment is another story. Something like that has never been achieved before. It's plausible that SpaceX will make it happen, but it's also plausible that it won't work. Then Starship will be simply an expendable upper stage that's too big and too expensive for the purpose.
Didn't the space shuttle used to do that?
Do you have any idea how many firsts they've put up? The craziest was reusable boosters.
For this one the problems to solve are fairly well-known. There is no particular reason to believe that it will be harder than what they already do.
Official estimates are that if SLS flies 10x, its cost per flight will be $4.1 billion. These things have a way of ballooning, but let's say that is reasonable.
SpaceX does not say how much Starship is costing them to develop, but external estimates seem to be under $8 billion. So for the cost of 2 SLS flights, SpaceX is developing a rocket with a cost to LEO orbit of under $10 million, and that they are aiming to get down to $2 million. SpaceX is planning to build in quantity, and launch at an insane cadence. Once enough have been launched, they will have ironed out the bugs and have a safety record good enough to take people.
After that, human spaceflight will be cheap.
In fact SLS is entirely unnecessary for going to the Moon. The current plan is for SpaceX to launch Starship, fuel it in orbit from other Starships, send it to the Moon, and then have it be a ferry for astronauts who got to the Moon on Starship. Why not just send people on Starship the whole way?
Yeah, yeah. I know the answer. Politics. SLS is largely funded by porkbarrel politics. Its purpose is to get congresscritters re-elected and only incidentally get to the Moon. But in a sane world, we wouldn't build it.
But we are. We are even laying plans to send humans to Mars on SLS in 20 years or so.
Anyone want an even money bet that Elon lands people on Mars before NASA does?