Very informative, thanks for sharing. I guess one of the assumptions behind this is the overall economy is good so the private companies can raise funding easily without going public. Emm but on a second thought, it shouldn't matter when economy is good as companies can always raise funding easily no matter from private equality or public, vice versa, companies may find challenging to raise money when economy is downturn no matter from private or public. So, maybe what you mentioned are the main reasons.

The cynical would assume firms financials the hyper-efficient public markets would mock prefer to swindle uneducated private investors.

True. But the money is too good on the public markets