Even if you take away half of the billionaires' fortunes it would work out a couple of dollars each for the poor by the time it got to them, and that's a one off payment.

Also most of their wealth is not real wealth at all, its just current market valuations of property they own. What do you think would happen to Amazon share prices if Bezos said he was going to sale all his shares? It would fall through the floor. So much of his supposed wealth actually disappears the moment he tries to access it. It's been shown millionaires in the 1920s actually had far more physical wealth and physical property than the billionaires of today even though they seem to be richer and far further removed from the rest of us. Their money exists in companies, companies which actually do things for all of us, not sat in their bank accounts.

The best way of raising large amount of taxes to help people out is to tax everyone and every company reasonable amounts consistently, which is why that's what every government does. Putting an extra 1% on a tax can raise much more than any millionaire windfall tax and do so painlessly and keep doing so every year.