Android and Chrome are not great examples. They already open source projects (or 99.9% based on open source AOSP and Chromium codebases), which themselves only survive because Google is funding tons of engineers to work on them.

The cut should be in the vertical integration stacks. Like in Apple's case between the hardware and OS, between the OS and the App Store.

In Google's case, their hardware is already open, they mostly keep apps in their walled garden (and take their 30% troll tax) with things like GooglePlay and other Google "services", not sure how that would be something to break apart.

Realistically, the best outcome we can hope for is breaking Ads away from Search.