As you just pointed out, the latter thing is, in fact, exactly what prevents you from simply building your own system: The network effect. It's why it's very unlikely anything but large governments like the US and the EU are capable of restraining Google's behavior. (Smaller governments are not able to, as Google would simply refuse to operate in those localities until the government caved to public pressure to stop "banning Google".)

I'd also caution you from describing Google's services as "free". The cost is huge, it's just not a cost you pay in dollars.