To my simple brain, the issue is quite simple
ISPs are facing higher costs because with services such as Netflix, people are swallowing more data than before.
Whilst Netflix may have highlighted the issue, they aren't the problem - the problem is that the ISPs have oversold their consumer packages, and now it's coming back to bite them.
Basically, if their current model is not sustainable, they need to charge more to the consumers who consume more data, and let the market sort it out (though I admit there are other issues to address here in the case of cable monopolies/duopolies)
Bottom line, why should Netfix pay more to feed in data (costs that would be passed onto the customer) meaning that ultimately, the cable companies would be charging more to watch a 3GB Netflix movie than it would to download a 3GB ISO.
The issue - the cost - is the amount of data, not the type, and if they have problems, they should charge the customer appropriately based on volume, and not offer unsustainable 'unlimited' packages at cost.