I've always understood good SF to be a thought experiment about an altered reality that reveals something relevant to us, today, right now. Usually it's a philosophical experiment; Philip K Dick was a master of this.

I've never expected prediction of scientific developments from SF, and I don't judge older SF negatively in any way for being "incorrect" in predicting things. Older SF can be less relevant because "now" is not "then", not because it made poor predictions. Predicting things is a mug's game in any case; it's easy to see something coming in any one single dimension (usually it's something we have in some form today, but lighter, smaller, faster, cheaper, more digital, more automated or more ubiquitous), but extremely hard to see it coming in multiple dimensions and the sequencing and interaction between different innovations as they unfold in parallel.

Sibling comments have referred to 1984 as a political fantasy with modern technology; for me, a political fantasy with modern technology is SF. SF as a genre is a very close cousin with fantasy; the chief conceit is more regard for what might be physically possible, and tending to be set in the present or future rather than a mythical past. Star Wars is fantasy in SF clothes (space opera); Star Trek is (usually) SF dressed up as space opera.