How much does Google pay MarkMonitor for this to happen?
They "make it up in volume" by giving you an incentive to keep your entire domain portfolio together, even when you really only care about MarkMonitor levels of care for a subset of them.
Advanced features like registry lock and local presence are also affordable-but-not-cheap.
(A lot of their more proactive brand and trademark management has been spun off to other divisions of Clarivate who acquired them some years ago.)