In 2008 there wasn't a need to click "install"? What OS were you on that provided Google Chrome seamlessly?
I was referring to search engines, though the same was true for browsers. Deals were cut with distribution channels to have browsers pre-installed and to have certain browsers and search engines as the default. The overwhelming majority of people would use the default. In fact, a lot of the benefit of releasing Chrome was that it became another distribution channel that would default to Google as the search engine.