I think a large number of people can't tell a browser and the search engine apart anymore. They are so entangled, internet to people means something that when they click on it, it shows the iconic Google search page. Wonder how that happened. I heard that Google is introducing Chromebooks to school kids. By the time these kids graduate, they'll be confused by any computer that is not a Chromebook.

I think if the OS, browser and the search engine belongs to the same company, its perfectly fine to set it as the default. As long as on first launch they give a clear option to choose something else.