But let's say someone is advocating for that 80%-90% tax-rate on income:
1. Why should I try to make more money if I'm going to be taxed at 80%-90%, forking over such a massive sum of my money as to make it mostly worthless?
2. Even if this advocate believes the rich don't need the money, what makes the government entitled to take the vast majority of their income? That was money the rich income earner made for themselves. I'd argue that it should be their decision how to spend the majority of it.
I'd argue that advocating for seizing such a high amount of money is very anti-capitalist. It's not really a government's position to regulate how much wealth someone "needs" when you have a high degree of freedom.
2. What makes them entitled to that money in the first place? Surely nothing other than the economic system which is grounded in a democratic negotiation. You may be interested to know that other languages don't use the word "earn" for income. For example, Spanish uses "ganar" which means "win". Just because you complete a task for which you are rewarded with money by our current economic system doesn't mean you have earned it (see also: people who think things are immoral just because they're illegal)
Sure, it's anti-capitalist. Why do you think that is a bad thing? I believe it's the government's role, because that extra freedom granted to the rich is taking what I consider to be far more important freedoms away from the poor.
Ayn Rand explores a world where the rich value creators go on strike when people and the government “loot” and plumber their wealth, through regulations and restrictions in her economic dystopian book Atlas Shrugged.
I mention this merely to suggest we could be careful about overtaxation ‘because they’re rich and won’t miss it.’ We ought to discuss the boundary where we go too far and steer very clear of that boundary.
There’s no real evidence to support that. Why must gross overcentralisation of capital be the only way to invest in productive activity?
If the rich went on a strike today; within a couple of years, they'd all be replaced by a different batch of newly rich people and the economy would be right back where it was before... Then after maybe a few more years, the economy would be in a better shape than it has ever been.
For every rich person, there are hundreds of even more talented people just waiting for an opportunity to take their place.
There have been many cases in history where all the rich people in a country lost their wealth and then they were replaced by a completely new class of rich people; Germany after WW2, Russia after the collapse of the USSR...
But if the capital were sensibly redistributed (I advocate for spending some on things like univeral healthcare, and then directly sharing the rest out) it would also enable a vast group of people to take entrepreneurial risks that are not in a position to do so now.