Black Mirror is about placing the mirror to society (hence the title). If you find the show childish, maybe because humans are childish?

there always seemed to be significant obstacles in getting there from where we are that are never explored or explained away.

Just my opinion but i don’t think it matters. Since the show is about putting the mirror onto society and how immature (and cruel) we are, my impression is that getting to the dystopian aspects is because we dropped the ball and allowed ourselves to submit to the darker and physical manifestation of our psyche that we see in technology spying or trying to kill us, or torturing a person over and over just to feel good about ourselves inflicting what we perceive to be “justice”.