Besides, with your particular method, how do you prevent people from over-bidding and then being unable to pay the fee?
No, whatever algorithm is used to select immigrants, wealth surely is not the thing to use.
As for those who don't pay up, immediate deportation without the possibility of re-entry. Combine this with a policy of enforcing immigration law, and we might get a workable system.
I also think that if you average over a long enough time span, it seems that those that hit the moon, money-wise, at one particular time barely break even over the long run. (Except they've already taken home their own salaraies, of course.) That's what I meant by it being a bad idea; at any given time the highest earners will, by selection effect, be those with the riskiest, most highly leveraged strategies. I can do without those, I think we need people that create wealth, not concentrate it into their own hands.
Absolutely. The recent turmoil notwithstanding, people "like those that worked in Bear Sterns" are enormously valuable to the economy.
Doing this, we import people who are most likely to be productive. To allow high human capital pople to compete, we could allow the immigration fee to be paid out over 10 years with a nation-dependent down payment required up front (e.g., $75k for brits, $10k for indians).
Of course, politically this is a no go. Politicians push immigration as a way of importing people to vote for them (e.g. dems want poor Mexicans and reps want skilled former Soviets); the good of the country comes second.