I guess many people think Sprint is likely to be acquired or evaporate, and many people also think AT&T acquiring Tmobile is a bad thing for competition - in the same line of thought.
I don't think so.
If AT&T and Tmobile remain independent, only Verizon will be the sure winner. Neither AT&T nor Tmobile will be able to challenge VZ in any significant manner.
In 3G world, 2xGSM and 2xCDMA foursome was a good balance. Now they will all move to LTE, reducing one will not hurt too much. But just 2 (VZ and ATT) is a bit too lonely for regulators - 3 is a good number. It is DEFINITELY better for both VZ and ATT to keep Sprint alive, in terms of competition policy.
For them, weak but independent Sprint - neiter alive nor dead - is an ideal 3rd one. If Sprint faces a serious situation to go under in the future, they probably will help behind the scenes.
Well, I may have been around in carrier world too long - getting too synical, I guess...