Rob, you seem to believe that personal wealth is cash that somebody hides in a mattress. Actually, personal wealth amounts to capital. Capital means things like hydraulic presses in a factory. People who make use of capital do it to produce more wealth, for themselves and for others -- otherwise known as "customers." Instead of producing capital, governments who steal personal wealth use it to produce politics rather than more wealth. Check Venezuela to see what happens when governments put a cap on personal wealth.
People who believe there should be a limit on personal wealth desperately need a course in basic economics. Thomas Sowell's book, Basic Economics is a good place to start.
I understand perfectly well that wealth includes machinery and factories etc. Russ, I am all in favour of that, and I have stated from the onset that the more the owners plow back into those things, the better. It is excluded from my pogrom on the über wealthy whose cash, when over the suggested limit, is not doing anything of much good for humanity.
As I wrote, repeatedly, the more businesses these folks open in order to use their pennies, if only to avoid paying them in taxation when over a limit, the better, exactly for the benefit of new employees and the customers for their products and services. I have no fight with that.
Put another way: money invested creating employment is good; money doing nothing but buying gold taps for the loo is also good, as long as you use all those loos. Money above a certain ammount, doing nothing more than sitting banked, is not good. And from a wider perspective than the just the owner's, it sitting banked is a temptation for it to get turned into unsupportable loans that will bring us right back to 2008, which I remember all too damned well.
I think it's quite easy to measure wealth that's not invested: you can start by adding up the value of the houses, the yachts, the cars etc. You can enjoy several of all of those and be well under fifty million bucks.