Yes, I think long-term there's a real risk that if there would be a deregulation of the limitations of charging and traffic handling practices of the ISPs, it would lead to a model where the internet gets sold cable tv style. More or less clearly, you'd have the ISPs selling packaged sections of web access: on one level you'd get Facebook, Amazon, Netflix, some popular newspapers, blogs and mail services, plus lots of shop websites, and so on - if you wanted unrestricted access to any web site that anyone's set up, the customer would have to pay a good deal more, and it would be described as a somewhat outrageous or luxurious demand, even if today that's the model we all enjoy. And whatever package you choose, the transfer speed might be higher for popular and established sites, those having also been selected by your ISP (though the precise practices of said ISP would largely be buried in the fine print or not spelled out openly to the customers at all).
The ISPs are grumbling about their not getting enough fat in return for their side of the market. For the last dozen years, they have had to fight with lean bids to sweep up customers; prices for transfer rate vs the monthly payments have been falling, and there hasn't been much space to cash in from the customers in other ways, if you put high prices on something there's always another ISP ready to dig into your customer base. This is all as it should be, it's the free market keeping prices low, and the risks of so many ISPs landing belly up that the market becomes a closed oligopoly with just a few big brands is very low I think, as long as they are not free to debit added costs for all sorts of pseudo-services of their own making or on a "cable-tv web" model. But of course the ISPs are going to argue with this policy of no differentiation in how customers and web sites use their broadband speeds - that all should be treated alike. That's why they try to pass net neutrality off as a non-issue.
I would argue, too, with Rubio's assertion that the internet has been founded and "has flourished with minimal government intervention". The network structure - fiber and phone cable highways, university networks, installation of web access points and contacts in new buildings and apartments, trains, railway stations, public libraries, the promotion of the web in education and all that - has been largely public funded and even set out by public decisions in many places. Many ISPs, in Europe and Asia at least, are old state phone companies that were sold off in the 80s and 90s but kept a privileged status on the market in some ways. Defence has been a huge customer everywhere and has driven the technology forward ever since Arpanet; even if most of the actual engineering has been made by private enterprises, it got off the ground because of the input of public money and contracts.
And the whole technology of the internet is largely founded on the space race, which was completely state funded: the need for remote control of processes over thousands of miles; better phone traffic routing; image recognition; automatic processing and filtering of large amounts of data, even automatic translation of texts; new, faster and heat-resistent circuits - all of this received a boost from the space programs. So it makes sense to see the internet as a public good, even though it's not public owned, and it should conform to high standards of transparency and open access (though of course not free of charge in all places, or with any demands that all one finds on the web should be in the taste of the majority).