You're missing the point. We're talking about the government potentially burning a 2 trillion dollar private company to the ground, and your response is to just shrug and say "oh well, the world will survive"? Yes, of course people will find alternatives. But you still just lit 2 trillion dollars of other people's private property on fire for no discernible benefit!
Your attribution of cause is wrong. We're talking about the government enforcing anti-trust provisions, and if the company is so broken that it cannot succeed without holding a monopoly, letting it fail.
Letting dysfunctional companies fail is supposedly a core tenet of capitalism.
I'm so tempted to just leave it at that, but in the interest of not contributing to HN's slow de-evolution into Reddit, I'll add that:
1. Google is arguably not a monopoly, all its products have at least some competition as you yourself already pointed out.
2. Whether Google is "dysfunctional" is a matter of opinion. It's not without problems certainly, but its also a highly successful company with millions (maybe billions) of satisfied customers.
3. A lot of the arguments for Google being a monopoly have less to do with market share and more to do with vertical integration. My point is that vertical integration has a lot of benefits. Trying to use anti-trust law to outlaw it would likely turn out to be very foolish.
If gmail disappears, people could move to another provider. Etc.