A bit conflicted - but I agree with the premise.
Our experience, which I no way would endorse as the only solution for everyone to follow, was different for each of our boys.
The oldest wanted a phone desperately and we agreed that as an 8-grader he could get one - he contributed $15/month and agreed that my wife could monitor his location, texts and calls. Throughout his teen years we never acted on the information, nor even referred to it in conversation. He's a good/great kid and this helped build trust.
The second child was one of two kids at the same age who didn't have a phone. This automatically excluded him from groups and activities and branded him an outsider. Getting him a phone helped integrate him into school life. He is also very active with school programs - pickup times and locations change constantly and his phone allows him to keep us in the loop. There have also been bullying issues that required us to get him "right now" - his phone has been a life-saver.
These have been our experiences and have worked out well for our family. I think the key is knowing our kids, their circumstances, and addressing their individual needs. Sounds like you have done the same with years, although with a very different approach-
Not easy raising kids, is it?