> More companies going public, earlier is better for markets and society.
I would disagree. Japan is a good example of a market where there are a lot of small public companies and they're largely held by the founders. There is not enough share holder pressure and these small public companies are often barely profitable and run poorly. I am sure there are other markets that are similar to Japan where there are publicly traded companies without enough buyers or liquidity or transparency, etc.
I wouldn't automatically say this is bad. If the money that would end up being more profits percolates throughout society, employees, communities etc., and even the founders themselves (as opposed to concentrated capital), it is actually fine and could produce a healthier society. On the other hand, I grant you that it might (also) feed corruption. But then, I wouldn't bet on concentrated capital not being corrupt as well.
Japan does not have a growing stock market index or economy. So Japan with aging population is not a good example. It does not grow in real terms. It's just an old peoples country at this point and for the future. Nikkei performed bad for decades