In short, a couple factors have made IPOs less appealing: 1. More regulation and reporting requirements 2. Hyper short term investors
The first incurs great costs, and counterintuitively reduces transparency. The second drives heavy gaming of the market. You can't hold a company accountable to day to day events, you probably can't even hold them accountable to month to month growth, it's an unnecessary burden and short term predictability doesn't correlate to long term value growth.
As a result companies wait longer before going IPO, and individual investors (read: the 99%) are no longer able to invest in the growth stage of companies. The implications of this are interesting: 1. Rich get richer, poor can't. Retirement funds and the likes get no real returns. 2. Things like second market, the JOBS act and more will provide real alternatives to the public market. Extend this out 100 years, the IPO market becomes day to day gambling with 0 connection to real growth. People will write algorithms to play this game, and it will roughly be a zero sum game. Private unregulated markets will replace the public market once individuals have the freedom to invest. They'll look like public markets of the past where there wasn't rapid trading and there were less regulatory requirements.
As a company, I would much rather list on a private market where people were only allowed to buy and sell my stock once per quarter. You could design an auction system that allowed the price to be set based on how many shares were requested to be bought / sold (could be similar to the way IPO prices are originally set). I wouldn't have to deal with short term ebbs and flows of the market, and worries of cascading crashes due to day to day events and rumors. Instead I'd get to release a comprehensive quarterly report explaining how the company is doing and why people should buy into our growth, and give a gameplan for how we plan to deal with crisis. Someone should build this, and figure out a way to let individuals invest.