Wait, what? Has this been your experience? My sense has been the exact opposite: the younger the person the more attached to the phone and the more sense of existential dread when it goes missing.
Eventually I confirmed with the lawyers that I could also take away their phones, and that broke some of them. I mean that I had troops break down in tears in my office when I informed them of the punishment, and some went to extreme lengths to circumvent the punishment and secretly gain access to another phone. (They still had laptops and Wi-Fi, by the way, along with permission to borrow a phone if they needed to make an important call.)
The Army has studied this a bit and found that not allowing troops to have their phones during basic training is a significant obstacle to recruiting right now.