Idk, I don’t think most scifi pushes the envelope of what we can imagine, rather it provides a convenient escape to galaxies less incomprehensible than the bewilderment of earth where the author can make a point about spacewar and unstoppable mindless empires.

shrugs

Scifi (like any other genre) needs to continually reaffirm its association with creativity, not assume because paper thin character types are fighting spacewars that it counts as pushing the envelope of our imaginations.

/end side rant