To be fair, it’s never assumed that a kid would have a phone.
An example would be if we are discussing a volcanic eruption from the 1960s and a kid asks me if the volcano has erupted recently - which has nothing to do with the lesson, but is still a point of interest. Instead of shutting down their interest, I might ask them if they have a phone and allow them to google it and tell the class. Now obviously if they don’t have a phone, it’s going to have little impact, and I can check later on in the lesson.
I also never ask if they have a phone directly because that leads to the potential for embarrassment. Instead I ask if their phone has charge/if they are connected to the school Wi-Fi/if they have any data left. So nobody feels the social pressure to have a phone.
Similarly with homework, I don’t directly say “note this in your phone” - I say “note this down how you normally record your homework” - and I also post it on Google classroom. However, not all kids have computers/tablets/phones at home, so I also offer them a paper copy (under the guise of “if you prefer to have a paper copy too” rather than saying “if you don’t have a computer” because obviously that reinforces a stigma for those who don’t have)
Its perfectly fine not to send your kid with a phone, they most definitely don’t NEED it. Despite what your kid will undoubtedly tell you. However, I’d say that at the start of high school, it’s maybe 70:30 phone:no phone, and by Christmas almost every kid has a phone.
I guess it depends how the teachers manage phones in their classrooms as to whether it’s an issue or not.