I actually don't think a DISH and DirecTV merger will happen with their satellite based services. The separate entity that runs DirecTV (70% AT&T and 30% TPG) also runs AT&T U-Verse and AT&T TV. Since the separate entity spinoff, they mainly market the AT&T TV product and only market DirecTV where broadband is not available. So that kind of tells you right there that over time DirecTV as a Satellite service is going to be phased out.
When you really think about it, Bell has been doing that in Canada for years. I remember seeing all kinds of Bell satellite dishes. They are quickly disappearing on urban areas and even half the ones you do see probably aren't in operation.