That won't always be the case as more and more people around the world come online. If the US continues on a SOPA/ACTA/PIPA path I could see some internet companies blocking them in the same way that a lot of companies don't do business in China.
Wrong. The vast majority of websites don't break US law. Not because they went out of their way to avoid it, but because they simply don't. These sites don't have anything to gain by blocking the US. Ergo, quite clearly, the vast majority of non-US websites have nothing to gain from blocking US traffic. Nothing at all.