This left over 100 wealthy foreigners remaining in the canton. Depending on how much wealth they had and how it was distributed, 55 ended up paying more tax and 47 less. Their total cantonal tax bill of CHF13.8 million more than made up for the losses, so the canton did better than break even.
Moving at all has inertia, moving to a new city in the same country has a lot more but I suspect moving internationally has the greatest. And the Swiss are a rarity in that they are one of few countries where native speakers can go to nearby countries and still be (mostly) understood.
So it's worth discounting the "if we raise taxes they will all leave" theory for my money
Taxes levied do not always equal the complete value to the economy of a country. While they might have been paying lower taxes, who says they weren't consuming/spending more? The cars they bought, the restaurants they visited, or the expensive suits they had tailored/made - those all add to the local economy. And those 'profits' are then also taxed, either at the corporate level (i.e. the restaurant) or at the personal level (i.e. someone employed at the restaurant).
Also, this said, there is only so much one can consume. A wealthy person might have 1000 or 10,000 times more wealth than an average person, but he doesn't have 1000 cars. Or suits. I would expect it to be better to have more wealthy people in an area, rather than less, even if the tax income is the same, because as a group they consume and invest more.
Economists do measure the "velocity of money". And it really is higher among the poor, for common-sense reasons; someone who's living paycheck to paycheck is (almost by definition) spending all of their income, putting it straight back into circulation, whereas the wealthy are more likely to save some (which yes does recirculate as investment to an extent, but the investor as rentier takes their cut, and investment income is often undertaxed), spend some abroad, or spend in less efficient industries (e.g. high-end handcrafted anything, where you're paying a master craftsman who won't actually spend a lot of their time producing things, and won't be pulling back anywhere near as much through the productive economy (e.g. buying materials) compared to the same amount of money spent on mass-produced goods).
I don't necessarily think this would be the result, but I can see a lot of people thinking that.