The problem is everyone has a different list of deal breakers that they need in a "dumb" device. It starts off simple, such as calls and texts, but some people want to play music, or get directions from maps, or maybe contact relatives with Whatsapp... Eventually you just end up with a smart phone.
Ideally everyone would just have the discipline to just keep what they need on their phone without trying to fix their problem with an overpriced gimmick that they will give up on after a few months.
Ideally everyone would just have the discipline to just keep what they need on their phone without trying to fix their problem with an overpriced gimmick that they will give up on after a few months.