OceanGate launched three people on a joyride to the bottom of the ocean and the sub imploded.
Rich people being willing to spend buckets of money on an experience is not evidence that it is "safe" or "cost effective", it's just evidence that there are people in the world with more money than they know what to do with.
Jet set was a thing in 50/60s Jet travel was viewed as a play thing for the extremely rich . Even today there is staggering 80% of the world population who have never flown in airplane ever in their life[1].
From the perspective of that 80% they can say airplanes are "just evidence that there are people in the world with more money than they know what to do with".
It takes a long long time for transportation to become affordable. What SpaceX has done so far is just make it a bit cheaper to make it possible for civilians to be able to even pay any money and do this. No innovation will be ever enough, that doesn't mean we demean it.
I'm not demeaning anything, I'm just pointing out that OP's argument makes no sense. There may be other evidence that SpaceX is safe and cost effective, but rich people paying them to go to space is not it.
Rich people being willing to spend buckets of money on an experience is not evidence that it is "safe" or "cost effective", it's just evidence that there are people in the world with more money than they know what to do with.