isn’t really mobile anymore, at least in its use.
People use their Smartphones in bed and on the couch just as much as they use it on the go. Mobile is ideal for reclining and is in many ways taking over the television as the primary screen.
The mobile phone is a companion device, untethered to the jean pocket. You probably have it in your hands wherever you are.
To be mobile is actually sedentary. More evidence below.