Depends what they're used for, if it's for lightweight-demands mobile communications and simple tasks then I'd definitely agree. However the phone has become the personal computer for many and covers a broad range of tasks, let alone before you consider demanding users.

If you've got one device for all your computing then you want something more capable, I think there's more scope for variation is when it's in conjunction with another device, mobile plus your choice of watch/tablet/laptop/desktop/etc. that doesn't necessarily have to be on your person or quickly accessible, task dependent.