You’re my favorite RPG grump!
I think sci-fi is so hard because the actual fabric of existence, society, and all the trappings are up for negotiation. I have an issue with spongy magic (as happens in World of Dungeons), and sci-fi can easily become all magic. The essence of rapidly changing technology is that there’s this sharp distinction between the possible and the impossible – but it’s always in motion. (“What? It’s going Warp 10?!”) Without crystal clear setting expectations, instead you just have mush. I think that’s why playing ‘Star Wars’ or other properties really helps to level set this. (In fact, Star Wars pulls away from this completely there’s AI, but they’re just metal people; there are laser guns, but they’re just revolvers; there are spaceships, but they’re just boats or motorcycles.)