maximize shareholder wealth?

[Nelson]

what's the point of maximizing shareholder wealth? when you have an IPO and the insiders of the company make their cut whats the point of even caring about the shareholders anymore. You've raised your money you can do whatever you want with it, shareholders can trade all they want on the market and assign any price they want to the share. Why do corporations care about maximization shareholder wealth? thanks
in response to Eddie's comment: so before the managers of the company used to work for themselves and now they're working for the owners correct? so what if managment is more concerned with making their paycheck than increasing owner's wealth? what are the incentives for managment to align themselves with owners view? Also what about facebook IPO and the killings insiders made? is that related? what is your view?