@northernlights @Radical_EgoCom Mathematical impossibility, depending on how you define "middle class." Piketty defines the working class as the lowest 50%, middle class as between the 50th and 90th percentiles. But possible to eliminate the impoverished (less than 60% of median income) and the current rich (top 1%), as opposed to the merely well-to-do (top 10% but not in the top 1%).
@northernlights @Radical_EgoCom Putting the max wealth at the Value of a Statistical Human Life would do that. Estimates for that value range from $7 mil to $10 mil, $11 mil in net worth needed to be in the top 1%. A wealth tax in that range would be about enough to pay for a UBI at 60% of the median income.