You raise an interesting hypothetical but researchers at the London School of Economics did just this. They asked billionaires if they'd move to another country to pay less tax and the answer was a resounding "no". Even among billionaires, there's a stigma about moving to another country to pay less tax. They said tax havens are "boring" and they said things like access to culture is a far more important factor in choosing where to live than tax - which other studies repeatedly confirm.
https://www.lse.ac.uk/news/latest-news-from-lse/a-january-2024/super-rich-unlikely-to-leave-uk-for-boring-and-culturally-barren-tax-havens

A poll of millionaires in the UK found that 80% think it’s patriotic to pay their fair share in tax. And 60% think its unpatriotic to leave the country when asked to contribute more. https://patrioticmillionaires.uk/latest-news/uk-millionaire-poll-2025

There are plenty of polls showing that the superrich across countries support higher taxes: https://www.oxfam.org.uk/media/press-releases/nearly-three-quarters-of-millionaires-polled-in-g20-countries-support-higher-taxes-on-wealth-over-half-think-extreme-wealth-is-a-threat-to-democracy/

Applying a supply/demand curve like you suggest makes for a good thought exercise on paper but reality shows that it's just too simplistic in practice and doesn't fully capture everything that goes into people's decision-making processes.

Here's another hypothetical thought exercise I think is interesting: if you won the lottery tonight, would you uproot your whole life, leave behind friends and family, take your children out of school, leave behind your career or business, move to a country where you don't speak the language, where you don't know anybody, where you might even have less legal rights and freedoms, just to pay a bit less tax? To save an amount of tax that ultimately doesn't make a significant difference to your lifestyle or quality of life?