One of the ways one can grow out of a fear is by accommodating it enough in a passive way that it’s forgotten about. Lighting up the back of a closet or under a bed for even a couple of months with a battery-powered nightlight (if there is no outlet available) could easily be enough for a kid to overcome it. Not in every situation, of course, but I think in enough that it could be worth a try.

I do agree that changing the entire space like that is too much though.