Back to $20, that's the fair value at which the management was willing to sell their shares of the company. Who would know more about the company than the management?
They actually thought $20 was too high and that' why they were offering their shares to the public instead of borrowing money from the Bank.
As to the investors? Greedy is pushing the price higher than the secondary pricing.
There will be more public offering if the price goes higher.
There is no such a thing as free lunch in this world.