I say this as someone that still loves (and writes a little) speculative fiction. Just a guess as to what’s happening.
It's still possible to imagine new bright futures, but that kind of imagination is very much against a cultural tide that's fervently regressive and nostalgic.
Vaccines put an end to endemic diseases which killed so many children every year. The birth control pill catalyzed the sexual revolution. We had a treatment for diabetes, which was once a death sentence.
The 1950s and onward saw huge changes in how businesses are organized due to computerization. In the US, cheap automobiles, cheap gas, the federal highway system, and subsidies transformed how most people live, including white flight into suburbia.
Plastic was a wonder material. Materials like nylon and polyester transformed the clothing industry.
That is a loaded term.