Counterparty risk assumptions

I'm a big believer in value investing and Warren Buffett's ideas of buying companies for less than what they're worth. But here's the part that I could never wrap my head around... Let's say a company's "intrinsic value" is $200 per share, but the stock price is $100/share. Ok, so that's a good buy then, you're buying "a dollar for fifty cents", as Buffett puts it. But, in order to make money, the PRICE needs to go up, because you need to sell it. You only own a tiny fraction of the company, so