There is a whole area of cosmology that looks at large-scale event horizons, they can exist in many forms, and yes the "drop off" point over large scales is somewhat similar but those far away galaxies actually appear more like what we would see if a galaxy was falling into a black hole, IE: they turn red and seem to fade away... this is because we stop receiving new information from them because the expansion of space is faster than new photons can reach us... this doesn't cut off sharply, it's just the last photons stretch out so wide that the waves may as well be flat.