I think she does overlook these scenarios, but when people aren't facing homelessness and other situations of desolation, then inter relating with others can be improved, in my opinion.Brown is also thinking of a utopia, and not real life.
I've found vulnerability to be something that enhanced my life and felt so right at the time, when not in crisis situations, so I don't agree that it is a utopian vision. I've also been homeless though, so I can definitely agree that it's not something to be applied in all contexts.
She just doesn't really cover all scenarios or think of times when vulnerability may not be applicable or realistic.