In 2003, Microsoft was ordered by EU to stop bundling OS with browser, media player and other software that seemed so important to them at the time. MS complied.
We look back now and think so what? The EU wasn't really wrong, so much as too focused on the issue-of-the-month.
Regulation of technology is necessarily painting in slow-motion with indelible paint using a broad brush.
We can't even compare to hypothetically breaking up Microsoft, because we could and probably still would have broken it up along product lines. Facebook is definitely more like Standard Oil in the sense that there isn't such a clear line to break the company up on.
Another difficult aspect of this problem is that the oil companies had physically distributed employees. Who is going to be assigned to the part of Facebook responsible for Florida? (Does Facebook even have any non-SV offices? Honest question, I have no idea.) The newly-created business to serve "the Southeast United States" without being located there is going to face some headwinds as the Baby Faces diversify. There's also some good questions around how to prevent one of them from simply winning in a way that a Michigan Baby Bell customer couldn't just decide to use Pacific Bell.
Break-up is a misguided approach. In the case of SO, it only served to make the consequently-more-highly-valued parts more acceptable to, and the whole more deeply integrated into society.
I think technology will again be the solution to today's evil-of-the-month. Which is not to belittle these real and important issues.