It will hurt them a little bit, because it will drive a few people to alternative platforms. However, the majority of their user base is now captive, because they have grown dependent on Alphabet for a number of services. All they have to do is ban a few people from all of Alphabet to set the example, and then 99% of folks will either subscribe or disable their ad blockers. Because getting banned from all of their services would really, really suck for most people who depend on them. Just think of how many non-Alphabet logins would suddenly stop working (either because of federation or gmail dependencies). Not to mention their data saved to the cloud.
Unfortunately, big picture is, they will come out on top. Because of the “embrace, extend, and extinguish” model that they are veterans at. IOW, they know how to royally screw people.
I think our only glimmer of hope is the government continuing to go after monopolies. That’s not much of a hope, though.