$50 for 100/20 is absolutely terrible. The most you should be paying is $30.
Google Fiber offers gigabit service for $70/month. That's 1000 down and up, according to their page. That's what happens when you have a company in the market that wants to be competitive, rather than trying to strangle you.
Even considering the greed of cable companies, I thought they'd at least be trying to make inroads with customers by this point. 3-4 years ago I saw that the cable companies' grasp via cable service was slipping, because of things like Sling TV and Pluto TV. Now Hulu has a similar service, Playstation Vue as well, and Amazon's doing similar things. I think I didn't take enough into account of the inertia of the short-term corporate mentality, and I go on about that all the time. All that means, though, is that once people start *really* running away from the big companies, they'll have less and less to offer, and will quickly have to go the route of massive giveaways and desperate attempts to woo back customers. Just going to be a couple of years later than I thought.