Okay I think you're intentionally missing the point. If someone isn't literate enough to make a Google drive account they are going to have a hard time with more things than a backup plan. They might not even be able to use a smartphone at all. We can nitpick the reasons why someone can't make a backup plan all day. What if they have a learning disability? What if they're in prison? What if they have no arms?
It doesn't matter. My point is if you can use a smartphone at a below-average level, without assistance, you can easily and affordably (free) have a data backup plan. If you can't use a smartphone at a below average level without assistance, you have much bigger problems than a backup plan and a backup plan shouldn't be one of your worries.