I’m not a parent, but going by pop culture, it seems like literally every child has the same fears.
In pre-modern times, I imagine that they’d be sleeping in the same room as the parents, but if modern notions of privacy don’t permit that, seems we could at least design an enclosed capsule or something.
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.