Much of it is possible, sure. I don't think most of it is feasible, or likely. Prioritization of classes of traffic is and has been a thing for a long time, and consumers broadly benefit from it (we all want VOIP traffic to have better latency sensitivity than Netflix traffic, and we all want Netflix traffic to have better bandwidth utilization than VOIP traffic, for example). (De/)Prioritization of individual products is a bogeyman that has yet to manifest outside of some products being excepted from mobile data quotas (Binge On, FB Zero, Wikipedia Zero).

Then you have things like the utterly ridiculous "your internet plan doesn't include commenting on this reddit thread!" stunts, which are either blindingly ignorant of the actual aims of net neutrality advocates, or are willfully deceitful (there is no technological way that an ISP could restrict or upsell layer 7 features given that TLS is a thing) - neither of which does very much to produce sympathy in me for the cause.

"Your single ISP could engage in behavior that doesn't benefit you" is an obvious threat - that's the threat of any monopolized market. But the vast majority of nightmare scenarios cooked up to scare the masses into action are, IMO, somewhere between fantasy and outright lies.