Of course I'm negative. The mere list of blocking problems for such idea can fill several pages even without expanding them.

First of all - nobody including Elon himself can estimate eventual Starship launch cost. Second - Elon have said that maybe it can come down to 2 mil and that most of that price would be fuel. So he was wildly optimistic as for production and maintenance of the actual hardware. In that interview iirc he was going from an assumption that Starship is already at the high end of reusability (multiple tens of flights or more) and flying regularly.

No one including himself published any total esimations for the total costs of the E2E system as whole and I'm pretty sure that 2 mil does not include any costs for platforms, transit to them, spacesuits, training facilities and dispatchers (new ones, outside of the existing in USA). Maybe he included start gantry, and some preflight checks. Maybe not even that.

Regarding platform cost, I think your estimate is way off. You are forgetting that unlike Elon's barges it need to be a) human rated, b) civilian human rated, c) internationally civilian human rated. It would need a lot of facilities for human on board, it will need some elaborate start rescue systems for 100 space suited passengers. Platform would need extensive protections from them the launch of this insanely powerful rocket (repeated and low on maintenance). Platform would need some kind of armored bunkers for the cryogenic fuels or an extra powered platform which can come for fueling and go away (x2 costs for two platforms). Some kind of evacuation facilities for hundreds of humans in case of a platform fire. A billion of things really. Each one platform will go to hundreds of millions, definitely not a mere 10 mil.

Fortunately I work in IT, so nope, any amount of automation added will simply require the same amount of even more experienced humans supervising them PLUS new people manufacturing, debugging and maintaining said automation.

Starship pilot would cost much more than an airline pilot. Maybe on par in the best case.

And I have to repeat myself - that's ONLY cost considerations. There a lot of other problems.

International permissions for airspace

Total time for the end to end trip (platforms will be VERY far from the cities, exponentially depending from the city size). As soon as that time exceeds 10-12 hours this whole idea is junk.

Total time to train civilian passenger. Total time to train old aged civilian passenger. Tha includes both for rocket, for escaping it, for using a spacesuit etc.

G forces. Why would older billionaires suffer that, potentially risking some aneurism or trombosis or worse?

100 passengers together. So you think 100 billionaires would voluntarily be packed liked sardines in the same confined space with one another? Lol, high society doesn't work like a lowly public bus to the factory.

100 billionaire passengers planning the same trip weeks/months in advance to the same city at the same time? Business does not work like that. They need to go anywhere at the moments notice, when they want, without waiting for a bus... erm.. Starship to fill up. And doing this not as a stunt once a year, but many times a day? Forget about it :) .

Things missing from the regular flight - comfortable private seat in the 1st or a jet (remember price would be so high that a even a big jet price would be cheaper, with all the seats together still cheaper). Comfortable talking and working conditions. Comfortable transit on land, not on a choppy sea. Comfortable suit instead of spacesuit. Gourmet food and alcohol. Chosen company. A lot of things.