I think a more effective solution than a breakup would be requiring Facebook to interoperate with other social networks. We could force them to implement APIs which would let users from other platforms chat with and send posts to Facebook users. Imagine a tweet or a snap showing up in your Facebook feed, and vice versa. ActivityPub[0] is already a protocol which tries to solve this, but Facebook would never freely implement it because it would breach their walled garden. We might be able to regulate them into doing it.

[0]: https://activitypub.rocks/