"But you haven't addressed the point about rich people leaving. They do do that, you know and the more money they have, the easier it is for them to leave. Look at Lewis Hamilton .... now tax resident in Switzerland ..."
Rich people say this sort of thing every time someone threatens their wealth. Sadly, they never keep their word. I was overjoyed when Labour got in because not only did I think we would get a fairer government than the Tories but Paul Daniels had promised to leave the country if they did. Sadly, the little weasel reneged.
Lewis Hamilton has gone? Good luck to him. If I have to see him less as a result, then we all win. I am sure that even Lewis Hamilton will accept that his wallet is not propping up the country unaided. We will muddle through without him and his ilk.
The bottom line is that:
(1) the majority are the financial backbone of this country and they are staying - not the tiny minority of high earners
(2) it is ultimately money that gets taxed, not individuals - any fool can make money in a bubble, and a genius can lose money in a crash. As long as it ends up in someone's pocket (and most of it does) it gets taxed and we all reap the benefits
(3) we all forget the concept of "sticky money" (a feature of the multiplier effect). Money spent locally stays local and keeps going around and keeps getting taxed. High earners, regardless of where they live, tend to have a large proportion of spare income which they invest. This tends to take it out of this "loop". In other words, low and medium earners are more taxable than high earners.