I agree with what you wrote, but the comparison is apples to oranges: Google customers are businesses; end users (who CAN switch easily) are the product.
Right now the only (supposedly) viable competitor is Facebook, but it's more of an advertising duopoly that divides the market - all the people I know who advertise say that you use FB for brand/interaction/marketing and Google for sales, and for a specific spend it is usually clear which one gets it (and seldom if ever anyone other than FB or Google).
Right now the only (supposedly) viable competitor is Facebook, but it's more of an advertising duopoly that divides the market - all the people I know who advertise say that you use FB for brand/interaction/marketing and Google for sales, and for a specific spend it is usually clear which one gets it (and seldom if ever anyone other than FB or Google).