If you put a 2.5% annual tax on net worth, that net worth would very rapidly find its way to other countries.

Wealthy people would learn to structure their earnings to flow into businesses in other countries to avoid this wealth tax. This would reduce income tax in the United States. I would guess the overall effect would trend toward a net tax loss.

If you gave 40 million people an extra $15K per year to spend, the prices of the things those 40 million people buy would go up. The poverty threshold would rise.

There are many second order effects like this that are always ignored in simplistic analyses.

It’s never simple math like taking one number, moving it into another column, and problem is solved.

The $15k is being transferred from entity A to entity B. Both entities are not spending the $15k so there wouldn't be any effect on inflation. If you printed an extra $15k then that would cause inflation because both entity A and entity B would be spending $15k.

Inflation, which means a steady rise in prices overall, happens only when the total money supply in an economy grows. This increase in money, often called "printing money," can be physical cash or digital money created through lending and government policies. Without more money in the system, if prices go up in one area, they have to go down somewhere else because the total money available limits how much can be spent on everything. Sometimes prices rise temporarily due to supply problems, but that is not true inflation unless there is more money chasing goods. This key idea, highlighted by Milton Friedman in his Nobel Prize winning work, shows that lasting inflation is mainly caused by increases in the money supply.

This I think is going to be a great problem that humanity must solve to move forward. Currently, wealth can become overwhelming concentrated and that wealth has mobility across jurisdictions which makes it nearly impossible to implement a wealth tax. The only way I see this ever working is enough powerful nations agree on a uniform wealth tax (say 1%/year) and those nations use their economic strength to pressure other nations to adopt the wealth tax as well. If the USA and EU got on board with a wealth tax I believe they could get the majority of the world to come onboard by implementing high tariffs on any country that does not implement the wealth tax. Of course the problem here is that the US is probably one of the least likely countries to implement a wealth tax, so I think this change will only come with major upheaval or violence.

A wealth tax is just not feasible because almost none of the rich will accept it. See almost any response to your comment as evidence. What we need is strong labor laws and the will for unions in the working class. A wealth tax doesn’t actually change any power dynamics. The rich are still powerful and the poor reliant on them. If the working class can band together, the power dynamics change and we can see some actual progress.

The end result of this logic is that poverty must exist for society to function and I just don’t accept that.

"If you put a 2.5% annual tax on net worth, that net worth would very rapidly find its way to other countries."

Most of that worth is in assets. If they leave the assets they can go.