Additionally, I think one could easily argue that the interstate commerce clause would prevail as States attempting to regulate interstate commerce. Otherwise, they could only enforce net-neutrality on connections entirely contained within their own state (good luck showing that's the case).
A lot of Services are headquartered in California: Apple, Facebook, Google, Netflix, Hulu, Yahoo, Dropbox, Reddit, Imgur et al. These services could well band together and lobby very influentially to regulate neutral access to all in-state broadband traffic. I don't think it would be very smart for the telecoms to push their tier garbage in California.