In the end ATT ended up paying hundreds of millions of dollars as a fine to TMobile. I doubt Comcast would repeat the same mistake.
This will largely go through with the ironic claim that they don't compete against each other, when they were NOT designed to compete in the first place.
Was that a fine? I thought it was a breakup fee common in merger contracts so that you can't have the other company show you all their internal details then you say "nah nevermind" and you walk away with their roadmap/customer numbers/etc.