Presumably whoever is doing the acquisition would look at the financial numbers in addition to the subscriber numbers? Then they'll notice a discrepancy between subscriber count and how much $ is coming in, which makes this whole thing unravel. It's far more likely it's just run of the mill incompetence and/or change of leadership prompting an "efficiency" drive.

The issue is that "whoever" isn't a single homogeneous entity. I would presume that someone in the organization spotted the discrepancy. Having worked closely with (and sometimes for) large corporations, I cannot presume that C-Suite decision makers were sufficiently aware of the issue. Or perhaps they didn't weigh the issue properly. Or maybe they were consumed by a desire to complete the merger, no matter what. There are quite a few ways this could have gone, internally, and still arrived at this place.