You still have to publicly reveal all the quarterly numbers, estimates for next few quarters, do all the GAAP accounting etc. which puts a lot of toll on a company that's going through wild swings in capital spending and production.

If they don't keep their promises, the stock will crash, so everyone goes on a production death march close to the end of the quarter under extreme stress, instead of just growing organically at a steady pace. Good estimates are hard, just like in IT. That's why many companies delay going public, for example Uber.