As a young child with ADHD and Autism, one of my first memories was being called out for daydreaming by the teacher. The problem is that daydreaming has been ridiculed even before there were smart phones, from having kids needing to be on Ritalin to pay attention to smartphones occupying our time, to the chaos of politics "flooding the zone" by taking away all those things about the government that were likeable. (I know this isn't the forum for it, but trying to shutdown the National Weather Service is probably the biggest assault on all those ADHD/Autistic people who liked playing with all the computer stuff the NWS produced. It was like once I found out about that, who needed The Weather Channel anymore?!)
The point is, we've been driven to be more "productive" than creative. After a while, that productivity creates burnout. Being prohibited from collecting your thoughts or wandering about other stuff has created more problems.
Discouraging daydreaming then making it into a commodity to be exploited by capitalism is probably the most terrible thing we have ever done.
We need to create a society that allows for daydreaming again, gratis. The phone is not the problem, only part of it. I can leave my phone on my desk or in the bedroom. We just need to stop being on-call for people who don't need--nay, deserve--our attention.