Are we in the Age of Failed Dreams?

Inspired to make these lists after re-reading Vernor Vinge's A Deepness in the Sky. I almost forgot what an incredibly awesome book it is. Ranks right up there next to the likes of Dune. And I realized I need to get my hands on the Vinge collection, and also reread A Fire Upon the Deep. Hopefully will write a review later. He is an amazing guy, a computer scientist specializing in artificial intelligence at San Diego State university and a multiple hugo award-winning author. Mini-spoiler: the humans in the story have been crawling around their neighbourhood of the galaxy at a paltry 0.3c. They think they know what cannot be achieved (faster than light travel, antigravity, immortality, aliens within visiting distance). But, like the reader, they're in for a big surprise.

Anyway here are my lists. Things that are sometimes reported in Scientific American, MIT Technology Review, Discover, Popular Science etc. But never seem to come of age. Are they failed dreams? Time will tell.

Physical impossibilities?

1. Time travel to the past (would violate causality - make effect precede cause)
2. Faster than light travel (In Eintein's framework of relativity would lead to time travel)
3. Fundamental limits of computation (amongst others) erasure of a bit of information always leads to dissipation of kT ln(2) of heat. Computation will always cause the processor to heat up, thus putting a limit on the amount of processing power that can be packed into a finite volume.
4. Quantum no-cloning theorem: it is impossible to make a perfect copy of an unknown quantum state. This is basically what makes quantum key distribution secure.
   

Failure of imagination?

1. A theory that reconciles quantum mechanics and gravity/general relativity (half a century after einstein's failed initial attempt and still no success)
2. What is the "Dark Matter" in the universe?
3. Why are there 3 space and 1 time dimensions?

Engineering limits?

1. Viable fusion (always a decade away?)
2. Superconductors for power distribution, transportation (ditto above)
3. Optical computers (what happened to them?)
4. Realtime portable translator devices for spoken language
5. Artificial intelligence at least as good as humans
   
6. 'Von Neuman' automata (robots that can scavenge for parts to build copies of themselves; there were plans (ideas?) to build a solar farm on the sahara desert with such robots, whatever happened?)
7. Nanotech machines of non-biological origin
8. Large-scale coherent quantum computers
   

Biological wet dreams?

1. Life extension; immortality
2. Tissue and organ regeneration

Economically infeasible?

1. Supersonic jets
2. Economical launching of payloads into space; cheap space travel; fast travel through space
   
3. Colonization of mars and other planets
4. Ubiquitous automation of menial labour
   

Just can't seem to find?

1. Magnetic monopoles
   
2. Aliens who use radio