If the keys are laid out in a 1x26 keyboard, yes. If the keys are laid out in a more usable way, then no. If I can see the key 'j', I cannot guess whether 'm' will be to the right or left of it, without knowing the length of the row, and considering it at all times.

I would describe today's society as one in which typing is necessary for any basic tasks, and is universal, and so I don't see why smartphone users would be different from the norm in terms of typing ability. Are you using "typing" to refer only to "touch typing"?