The US start rate is functionally zero. Other than a handful of Silicon Valley wunderkind, most new fortunes are being created by finance or professional managers. The problem is the manner in which those people are extracting those fortunes.
For the former, this'll do to explain it:
https://tcf.org/content/commentary/graph-how-the-financial-sector-consumed-americas-economic-growth/
For the latter, it is a different, fairly technical discussion.
Something like 70%-odd of CEO compensation today is in the form of stock grants and options on average. Due to some complicated scheming, this stock isn't awarded from a designated ISO pool (incentive fund) like your stock grants would be, but instead by issuing new stock. Issuing new stock devalues the stock held by all other shareholders, in a process called
dilution: it means that every outstanding share represents ownership over less of the whole company, and since the market has decided that a company is 'worth' a certain amount in aggregate, the value of each share declines. To get around this drop in share price, the CEOs order the company to buy back its own shares, imposing an effective price floor on the shares, and increasing liquidity so it is easier to sell the shares they issued themselves.
The net result of this is that professional managers - the C-levels, in particular - skim almost all economic growth right off the top. The rest is taken by finance for management fees, as discussed above. And the result of that is the real owners of the companies, the shareholders, have less money to spend on more productive enterprises, and the companies themselves are starved for reinvestment. Perhaps 35, 40 years ago, all of this was illegal. Stock buybacks, in particular, were considered insider trading by the SEC. Today, though, they are standard practice.
If you ever wondered why companies wither and die when their founders retire, this is why: because professional managers are parasites.