So are you in favour of both abolishing physical cash and negative interest rates?
(larger than now, how big a negative interest rate are you in favour of? Nevermind: I see from your other comment, 5%, immediate bank run territory.)
You realise lower financing costs do the opposite of encouraging long term thinking. The inflation cost is merely moved to deflation cost of cash.
What do you mean by a post capitalism system?
You realise that hyperinflation contributed to WW2, and that in the event of negative rates the rich move out of cash into another asset(like housing). See Roosevelt and the gold standard. I honestly doubt that negative rates would have avoided the Great Depression.
Wealth taxes also reduce inequality and can be more progressive than negative interest rates which hit middle income earners the hardest, who try to save for retirement.