It hasn't happened with Netflix on any large scale, yet. But it has happened in the past. There are videos games that are single player and can't be played without an active connection back to the publisher. What happens when the publisher doesn't like you or mislabels you as a pirate? What if you just want to play the video game you bought and payed fro without an Internet connection?
There were music stores that only played music through special software after getting decryption keys from an active connection to the Internet, and some of those stores shut down. What happened with the millions of dollars paid into those stores? What about the songs? Did you know that decrypting a song you bought and paid for is a crime?
Consider: https://xkcd.com/488/
I would rather get out in front of this entirely artificial problem before I have to support my friends and family who don't understand the nature of this problem.
I do agree with you for purchases that have DRM, but this is a subscription service - you watch when you pay, not when you don't.
But why can't I use their service on a device of my choosing at a resolution of my choice? Why is my perfectly capable Ubuntu machine limited to 720p and a windows machine isn't?
Having some kind of standardized access where I didn't have to put up with their BS would go a long way towards making that easier for me to deal with.