It's not. This was planned. It was the objective all along. Why else do you think Google Maps is free? Gmail? Why did they drive around 1,000s of cities with cameras on a car taking photos for Street View? Was it really just to become the world's most comprehensive search engine? Hell no, it was to get people into the ecosystem and to stay there, and be content with doing so. Just think how much money and manpower went into each of those free products we take for granted, not the least of which includes the Google search engine; now think about how they make so much money off your attention that they can offer it free of charge, because sucking you into the ecosystem is just that profitable.
Chrome is the same thing. Why would a for-profit company develop a web browser more or less unprompted and give it away for free? To draw people into the system and get them comfortable with staying there. Now that they have monopoly power, they can start tightening their grip with the good old embrace, extend, extinguish.
Google isn't unique in this. Similar arguments could be made about Facebook.
To be sure, Google and Facebook have produced tremendous advances in science and technology. But let's not forget what funded them, or why they were developed in the first place. Lest we forget why these things play out the way they do.