>> I've recently read stories of startups that became successful and were bought out for large sums, but the founders received little from the transaction.

It depends on what startups you're talking about, there are many reasons as to why this could happen.

>> Also, how do cases like Steve Jobs and Harry Osborn occur where they are removed from their own company? Do VC's and Investors really take that much of the company? How much influence do they hold over a company they invest in?

Apple was a public company at the time, and Steve Jobs was forced to resign by the board, just like any other employee can be forced to resign for whatever reason (unless they're in control of the majority of board, ala Mark Zuckerberg). He still owned a large share in Apple after he was fired, which I believe he mostly sold off.

>> Why would a founder continue if they lost their ownership? Why would a founder give up ownership of their company in the first place? Isn't one of the prominent appealing aspects of the start-up world to own your own company?

Most good founders don't want to give up ownership, but if you want to receive funding from investors, as far as I know there's not really any alternative to giving up equity in your business.