I don't think practicing hand flying in the sim every few months would make the slightest difference.
To retain hand flying skills you have to be doing it every other day.
Par for the course in some types of operation.
Impractical in others.
I don't think there is a solution; we are just in a point in the development of aviation where a gap has opened between economics and human factors. Presumably the gap is economically acceptable right now and will close as technology improves.