We are lucky enough to have a cell plan with unlimited data. We stream movies etc. quite a bit. Unfortunately, where we spent the winter had very poor cell data (ATT). The campground had great connection, since they had towers interspersed throughout the campground, but of course the bandwidth was inadequate. I have been to one campground where we were able to stream without a problem, and that was at Lone Star in Austin. They gave you a password for each day that you paid and for each device. It was an outside provider. I'm not sure how they provided that much bandwidth, but it seemed to work well. I wouldn't have a problem paying 30-40 bucks a month for the time that we are in Texas for the winter for dependable, high bandwidth service. Most of the campgrounds have not maintained their phone lines, so this is probably not really practical any more.
I don't think that many campers or campground owners really understand the difficulty of providing internet service on a level that folks have grown accustomed to at home.