5 years is about as long as a console generation usually lasts, and this has less of a buy-in cost than either PC or console gaming. If it runs for 4 years and

5 years is about as long as a console generation usually lasts, and this has less of a buy-in cost than either PC or console gaming. If it runs for 4 years and makes money, that's a success for Google. It doesn't need to be permanent to be useful.