Money is invested because people with money chase yield, if yields are positive, but lower across the board, that money would still be making the exact same investments.
But it's certainly not the case that people make the "exact same" investments with or without taxes, especially of course as taxes get higher. Money will shift out of investment to consumption as expected profits decrease, or indeed out of the tax regime to other areas or to black markets.
the goal is to have investments that serve broad interests. instead of investing in better yachts, supercars, jets, etc.
instead of investing into Amazon to dropship fake shit for quick bucks our economic surplus ought to go into developing better actually useful appliances, tools, technologies
for example, instead of OralB and Philips bamboozling us with sonic this and that with smart AI toothbrush marketing we ought to actually figure out dental care.
okay, sure, higher taxes on the wealthy doesn't guarantee more conscious consumerism, but might at least give it a chance.
Except on the middle class. All capital gains do to middle class workers is ensure they stay middle class