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.
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.