Your point seems to be that we would have good metrics to evaluate the actual impact of these anti-competitive practices, including everything that didn’t happen because of them, and can apply proportionate punishment that would repair the damage done.
I don’t see any of these two assumptions to be true today, and if the point is to apply heavy enough fines that Google’s behavior radically changes, we’re not that far from for instance just breaking them up or applying specific restrictions on them.