I understand your opinion, and you're of course welcome to it.

However, billionaires don't "hoard cash" as you claim. Their billions are in income-producing assets such as real estate and businesses. Thus, they create jobs that help people make a living.

You could argue (and I'd probably agree) that Amazon should pay more to its employees, or perhaps give them non-voting shares in the company so they benefit from increasing the company's worth.

You could also argue, and I'd definitely agree, that tax laws should be changed in a way that makes their progressive nature actually effective, which is what some of President Biden's recent proposals target.

This includes making capital gains taxable at the same rate as wages (I'd argue that we should actually give preferential treatment to wages, since we all have the same 24 hours in a day, so if you're working then you're giving up something valuable that can't be replaced).

It also includes doing away with the basis step-up when people bequeath capital assets to their heirs. That way, society gets to benefit from the taxes assessed on that growth.

In short, instead of seeing wealth-building as somehow intrinsically immoral or evil, we should celebrate its success, but make sure it's taxed at least as much as wage income, with no loopholes, so an appropriate portion of it gets funneled back to society at large, without expropriation or nationalization, which characterized the failed experiment of socialism.