I think Comcast doesn't realize the data cap issue could be MUCH more serious than they thought.
It may be more than just a streaming video problem from Netflix, Amazon Prime Video, Hulu, and so on. The likes of Apple, Facebook, Google and Microsoft are pushing for more and more operations "though the cloud," and that could really use up a lot of data over the Internet in the near future.
I believe that the downfall of data caps won't be a lawsuit from Netflix, Amazon or Hulu, but from Apple, Google and Microsoft as these tech companies embrace more and more "cloud computing" initiatives. And Comcast doesn't have the deep pockets of Apple, Google and Microsoft when it comes to legal wrangling.