In reference to the above, I was curious, so I compiled this list of the existing operators that have CDMA2000 / EV-DO / LTE in the US, (compiled from Wikipedia)
Now, not taking Verizon or Cricket Wireless (being sold to AT&T) and only taking those with known subscribers, even if Softbank were to buy them, it would only amount to an increase of 8.88 million for a total of 61.76 subscribers from the existing 54.88.
I'm not financially able by any stretch of the imagination but I would think that the ROI won't be great enough to justify being able to buy out these operators.
TS