No startup is truly defensible against a company with tens of billions at their disposal. "Google could clone it" is so obvious that it doesn't seem rational to even consider it a problem. Yes, they could. You can't let that stop you though.

It's far more sensible to worry about your idea being cloned by a teenager in her bedroom who could give the same product away for free a week after you launch. That's the real threat for most startups.