Maybe it helps if you think of yaoi and slash as in the same set as romance novels? That might explain why the personal and sexual relationships are the be-all and end-all of the work, and why there's an absence of things like economics, politics, hard science, weather, and women. It's just the givens of this very artificial genre. Add balance and a wider world-view to either yaoi or slash and, quite simply, they aren't yaoi and slash any more, but mainstream lit with m/m content. And at that point they also cease to be sexual fantasies, which is their other main function in life. Porn is not known for its balanced approach to the human condition.