Novice users use flash drives or emails, they don't set up ssh servers. In fact, I've never seen a non-power user set up an ssh server except maybe if you count a consumer NAS (which usually show up as networked drives).

To that point, I'd be willing to bet money that any user that even has access to an ssh server they'd want to use either has the technical know how to set up those tools themselves, or has an IT person who can do so for them.

On the OSes that have SFTP capable shells ssh is enabled by default.

Other OSes lacking this is why everyone keeps their data in silos.

This still doesn't answer the question of why a novice would want SFTP.