If space was filled with just electrons then the medium would offer the ability to form a dark energy type of substance. We know like charges repel and all the electrons would be repelling each other and creating a non collapsible medium around the object they are still bound to. Im not just blindly guessing, im trying to find relationships between the small and big (GR and QM) with what is proven and available. it is imaginative guessing, but not blindly since I am using whats available to work with. If you dont try and find, you'll never find anything. And I accept that a lot of the time I will be wrong, but being wrong isn't bad or stupid, because it will eventually expose whats right.