Well, you could look at it that Verizon has some projected profit margin and they set their rates accordingly. Lets say 20%.
So, if they give you a $600 phone that costs them $400 for $99 with a two year contract at $79 per month, where their total costs involved to give you a months service is $50, then
You pay $79x24+$99 = $1995
Their cost $50x24 +$400 = 1600
Just about 20% profit on the nose. Now, lets say in two years [when your contract is up] their costs go up 6%:
You pay $79x24+$99 = $1995
Their cost $53x24 +$424 = 1696
Profit is now 15% and the investors are mad and they won't have that, so:
You pay $84x24+$99 = $2120
Their cost $53x24 +$424 = 1696
If your data, in aggregate [ie, not your personal data, but the combination of millions of users] is worth $125 per year. Instead of of them raising your rates to match the increase in costs, they could just sell this aggregate data and keep your rates the same.
I suppose in that case, it'd be something like them deciding for you that you'd rather have lower rates and don't care about your data as a data point among millions versus you having higher rates and that data not being shared. Would I rather have the choice? Sure. But I don't think it is a big deal.
Granted, I'm sure that somewhere on the contract I signed, it said they have the right to do what they please with this data, so it probably isn't my call anyway...