I was reacting to the word primary. I think that is a common (especially on HN) misconception. The markets make more sense when you don't think of them as mechanisms to fund companies, and do think of them as ways to trade risk and liquidity.

I'm not convinced that the capital allocation component of the markets is even as you say "necessary". You could easily envision the markets chugging along fine without allowing any direct sale of equity to the markets. That is some intermediary would be required to buy the equity from the company as it became available and in turn could then sell that equity into the markets. We are almost to that point already.