> The top 50% of earners already pay 97% of all the income taxes.
Personal income taxes are about 58% of taxes on personal income. The other 42% are the much more regressively-distributed payroll taxes, where the middle and upper classes pay less-to-none while the working class pays heavily.
> The US has one of the most progressive tax systems in the world.
[citation needed], but even if so then it more than makes up for it with the distribution in spending; considering taxes and spending together, the US has consistently been near the bottom at policy progressivity (measured by post- vs. pre- transfer change in Gini coefficient.)
> How much more progressive of a system do you want?
At a minimum, not giving preferential tax treatment to a form of income received predominantly by the super-rich (long-term capital gains); while there is an argument that income earned over multiple years but realized all at once should get taxed in a way that reflects that in a progressive system, a step reduction for long-term capital gains is not a sensible way to do that, as it both reduces tax on income for which that doesn't make sense and misses much where it does. Allowing options time-shift income for tax purposes (free advance recognition and limited deferral) does that better, handles thing like artistic projects that are developed over years and then realize income over a shorter period later as well as long term capital gains, but doesn't give tax cut for long terms gains that wouldn't change tax brackets even if spread out over the full term the asset was owned. It is much more fair as well as more progressive.
> Unrealized capital gains are imaginary
If that's really true, the LTCG are just windfall income that should be fully taxed in the year received. It’s not, though.