You're right that the propensity to spend is higher among low-earners, so if you're trying to stimulate the economy it makes sense to allocate there (all other things equal). But my point was about the futility of trying to use a wealth tax to cut down on generational transfers of wealth/advantage. If you tax wealth, that encourages people to spend instead of save. And if their concern is keeping their family in the top 5%, 1%, or .1%, there are plenty of ways for them to spend it in order to achieve that end.