Virtually everything you said is either wrong or is the same as the comparison The two satellite radio satellites were not compatible. The receivers were not compatible. Look it up.You can't compare the Sirus/XM merger to a possible Directv/Dish merger. Other than the fact that they are all four in the media delivery category the main difference is in the logistical differences. DirecTV and Dish cannot directly use each others satellites. The on site equipment (dishes, dvr's, remotes, etc)is not compatable. Plus DirecTV/ATT is not vested in growing the satellite end of the business. As they move into the 5g arena ATT will concentrate on the streaming end of their business. When Sirus and XM merged it was a growing profitable endeavor while satellite TV is a dying and becoming a less profitable endeavor. In 5 years the satellite business as we know it will be a shell of itself. A dinosaur relegated to the "once upon a time" scape heap.
You said - "Plus DirecTV/ATT is not vested in growing the satellite end of the business. As they move into the 5g arena ATT will concentrate on the streaming end of their business." ???? Yes, the whole reason they will not want Directv to begin with, that's the whole premise of the discussion! DISH is not in that position.
You said -"When Sirus and XM merged it was a growing profitable endeavor while satellite TV is a dying and becoming a less profitable endeavor." It's in the links I provided no they were not. I don't know if you were old enough then to have been aware etc, but I was and a big believer as I am now of it. I can tell you no they were not there was a good chance as two companies they would have not made it. Both were weak companies moving towards failure exactly as PBS said of them.
No one can predict is my point if you took the time to read my links that is clear. Even "experts" got it totally wrong. If Satellite TV can remain to be a competitor to Cable, 5G, whatever, with combining companies then I believe the FCC would allow the buyout or merger just as they did with Sirius and XM.
No one knows what At&t will do or try to do, if there is another buyer out there, etc. But I totally dismiss the idea the FCC would never allow them to merge just as they would not let Satellite radio die out without letting them merge. The FCC was proved 100% right to allow that merger as the new company has far more subscribers than the two separate ones did and offers lots more entertainment, better ways to listen etc....