There's yet not enough devices connected to the internet wiling to share their data. There's a whole lot of companies that need to be created and things to happen (which might never do) for something like a data marketplace to exist. If that ever happens, any company that has the resources to make sense of additional -targeted- streams of data (as they already effectively do) should be able to turn a significant profit from the acquisition of said data. Either for product customization or advertising - or both.

For every transaction a bank processes there's obviously a fixed cost. Once you account for all the costs relative to them in a given year and divide that number with the number of transactions in that same year, I doubt, given the margins of a given transaction, that a bank can break even on 1 cents transactions. That's assuming that the tech the banks use as of now does not improve by magnitudes in a couple years.