Yeah, I heard that rich **** argument before. But if they move away when they have to contribute, they are of no value anyway. Just make a law that they have to pay up as long as they are citizens, like in the US. Problem solved.
There are a number of countries which offer their citizenship in exchange for investment. And they are not all shit holes.
But there is even more important matter. You propose to virtually discriminate one group of people and to solve some problems of another group thanks to that.
When people are talking about the rich they often have in mind the bankers or financial traders or other 'fat cats'. Sometimes they mention the descendants of rich families who did nothing to gain their fortunes.
But I often imagine IT sector. It is the field where many common people made their fortunes purely thanks to their intellectual and hard working abilities.
So, if say Peter founded some company several years ago and now is gaining 3 million dollars of net income annually, will be he considered rich and have to share his fortunes with the poor?