A breakup is highly unlikely IMO. Not only has the U.S. govt not been keen to break up monopolies in the last ~30 years, but it actually let AT&T reconstitute itself by re-acquiring most (all?) of the former baby Bells ~20 years after breaking them up.

In addition, the current administration has taken an absolutely anti-regulation approach if you get/stay in their good graces. I suspect that something closer to a toothless consent decree with certain <cough> accommodations to the administration would make this all go away. Not saying it's right, just that it seems the most likely.