Maybe it's not the phones per se, but the fact that most of the software on them is written by people whose business model is primarily about distracting people

Maybe it's not the phones per se, but the fact that most of the software on them is written by people whose business model is primarily about distracting people from whatever they set out to do and getting them to do something else instead. Learning requires a modicum of dopamine hygiene, and dopamine hygiene is bad for business.