There are so many reasons for going public, that it's a little difficult to address your question.  My own experience is in this California high tech/health care start up environment.  I would say in 80% of the cases, the reason for going public is that the original investors, who have made an investment that is very risky from their personal perspective, want to "cash out".  Remember that all their investments are not winners, they lose their full investments on the losers, so it's only fair, IMO, that they get a chance to cash out on the winners.

And for this size company, which would normally have sales revenues of $30 million or so (obviously company's like Google are an unbelievable exception to the average startup), even if their investors didn't need to cash out, borrowing from a bank is incredibly expensive as opposed to going public, and having shareholders share the risk of future expansion.  So getting money to fund expansion from equity investors, as opposed to banks, just makes logical sense.

In my experience, maximizing shareholder value is not consistent with driving a company into the ground.  Building shareholder value means building a real company, that meets customer needs, and introduces incredible products, better than the existing products,,,, and then replacing those with better products.  I know the companies that hit the headlines are driven by ,,,,pejorative term,,, people that I would like to see jailed, but it's just not the normal person in business.

You are correct that a company's stock price is influenced not only by their results, but by the overall market valuation, influenced by interst rates, and other factors.  But in terms of leading a company, you are a fool if you get taken away by that.

I'm very discouraged that so many people's opinion is driven by the Enron's, etc.  in general, people that run business, IMO, are just as good in a values sence, as anyone else--in my experience, which has been in healthcare, it's been higher.  My own experience is filled with people, at all levels in a company, that work their tails off, to come out with wonderful products, consistently at the highest quality, that meet the needs of physicians who treat patients with these products.  it's always very depressing to read the press, who highlight the errors that are made, the people that have bad motives, etc.  it seems to me like picking an ethnic group, and based on the highly publicized activites of a few, discriminating against that group.  It's just not fair.

And responding to your close, my experience is more real world than business school--take that for what it's worth.