This objection has been brought up repeatedly but these are solvable problems.

Firstly, a lot of assets the wealthy own cannot be transferred out of country. Stock in companies, real estate, etc. The super rich are not rich because they have bank accounts with all of their money that can just disappear overnight, but because they own real things in the real world.

Secondly, economist Gabriel Zucman has proposed a solution to the “they will all take their money and leave.” The USA taxes all citizens on their income no matter where they are in the world. You could simply create a wealth tax that says “if you have wealth over 100 million USD and have lived in this country in the past 5 years, you have to pay the tax no matter where you live for the next X years. (X could be 5, 10, 15, whatever.) If it goes into effect starting in some future date of course people will try to shift assets and move but if you make it retroactive they can’t. Also the tax needs to apply to companies so they can’t have an LLC holding all of their assets tax free neither.

Finally, taxing wealth is not about being jealous or craven that others have more. It’s about survival of society in some form that isn’t “ten people own everything and the rest live in desperate poverty.”

For the ultra wealthy, their wealth can grow passively from compounding interest leaving them will little choice but to continue acquiring assets. If you were given a million dollars every week (that’s roughly 5% annual growth on a billion dollars) you would quickly find that you had lots of money sitting around despite paying off all of your debt, upgrading your house, having fun trips. Eventually you would start using that money to either buy stocks, real estate, etc. Then those things appreciate and your $1M per week begins to climb despite living a lavish lifestyle. It’s just a natural consequence at that point that you buy up and own real world assets at an increasing rate. This means there is less and less available to own for everyone in your community.

Essentially, at a certain point these individuals become financial black holes where their wealth is not only self sustaining but continues to grow and consume things. There is no stop unless society puts brakes on it to limit the growth beyond a certain point.