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.
Letting dysfunctional companies fail is supposedly a core tenet of capitalism.