Access to the world's information is at present almost completely in the hands of a few large companies and largely in the hands of just one. As an aid to thinking rather than shopping, diversity in search might be crucial. Lack of such diversity might be bad for business, but might be even worse for humankind.
Google works very differently from other companies that have been dubbed "gatekeepers" and that are regulated accordingly. We are not a ferry, a railroad, a telecommunications network, or an electricity grid with only one line serving you and no competitors allowed. No one is stuck using Google. People have choices, and they exercise them all the time. We know that if we cease to be useful, our users will leave. The barriers to entry are negligible, because competition is just one click away.