Most bubbles trickle down. VCs will gladly partner with companies at high valuations because eventually banks, accredited investors, and secondary markets are let in on the deal to drive the valuation higher. The first two groups pray for and/or plan an IPO to dump an even higher valuation on the public market.
Boom is the transfer of wealth from the bottom 95% to the top 5%. Bust is when that transfer is complete.
I've heard these arguments a lot, but I've never seen anyone point to a specific case where someone with under a $50,000 a year income ends up with these stocks. Other than employees of course.
I think this inflationary period is probably closer to past ones (e.g. microcomputer/peripherals in the early 80s) then the wide spread financial asset bubble of 2000.
And if we hear about more of these 'special purpose vehicles', the public/private distinction may well be on its is way to irrelevancy.
Further, the article is a very well-thought and argued piece that doesn't remotely veer into hyperbole. Even if you disagree with its conclusions, it strikes me as incredibly disingenuous to dismiss it as "just another Chicken Little".
I'm not sure whether it's the S-O that's actually keeping companies from going public now.
An alternative scenario is the rise of a hypothetical trend in listing on non-US exchanges.