Nokia isn't the only one that makes feature phones. Kyocera, Samsung, LG, ZTE and Sonim are all relatively well known companies that make them. While they're not as varied as they were back in the early 2000s, a lot of them have various stand out features, such as ruggedness for construction, no camera for security, LTE tethering for when you have to get work done on a laptop or tablet, etc.
Me personally, my flip phone has been a breath of fresh air while I'm out and about. I think the one thing I really miss is being able to look up businesses and addresses on Google, but that's about it. Other than that, it's been great. I don't worry about dropping it, the standby battery lasts me almost a week, call quality is great. I even get complimented on it from time to time, to which I respond with "Thanks! Know what the best part about it is? IT'S GOT REAL BUTTONS!"
I've been seeing more and more opinion articles like this one. I'm starting to think, similar to people questioning Facebook and such, if we'll start to see some people decide to downgrade to feature phones for a digital cleanse. I don't know who, and I don't know where, but I'm sure there's some millenial hipster out there rocking a jitterbug.