What limits the rate of entrepreneurship?

Schramm's Law is that "The U.S. economy needs to spawn something like 75-125 billion-dollar companies per year to maintain the post WW2 rate of growth." In 2013, when the venture capitalist Aileen Lee coined the term unicorn, there were only about four unicorns being produced every year. By 2021 this changed dramatically: 264 companies in the United States reached unicorn valuations, well above Schramm’s law. Will this result in the post WW2 rate of growth?

The venture capital market has been growing rapidly, primarily driven by large, later-stage funds and the expansion of non-traditional investors in VC. VC raised record numbers of capital in 2021, around $100B. Still, this is small in comparison to private equity which raised $500B. Technology can disrupt many of the old school businesses in the public markets meaning that VC should continue to eat up more and more of the market share.