That would be me.
I don't own a cellphone since 2004. I've got tired of being constantly available (and disrupted), so I ditched the damn thing. It may not be practical for everybody, but it works for me. The world has its own pace and I have mine.
For me, the biggest inconvenience of not having a cellphone are those businesses (websites) that insist on a "cellphone #" being a required field during a sign-up or when requesting a quote.
Disclaimer: I run my own show.
I think with 'smartphones' being so expensive that phone contract prices in general have gone up. So far I've never owned a smart-phone and hopefully I can stay away from that bloated cost.
Disclaimer: I live in suburban amerika in a moderate-sized city with a low(er) cost of living. (Think LA is 1.5 x more expensive then here.)
...And yes, I threw in a Rammstein reference.
I do appreciate having a map with me, being able to transfer money wherever I am, take a photo without carrying a full camera, read a book on a plane without adding the weight to the luggage, have some music available when I'm bored, not having to print tickets when possible, having all my notes/calendar without carrying an actual notebook, and a number of other things that simply improve my life without any downsides.
You can say that Knuth went of the grid to accomplish something extraordinary, but I did it once I've realized that my life is actually mine to live and that the world would not end if I'm not reachable. I quit being Atlas and the sky didn't fall.