Well, speaking as someone who has a professional interest (and enthusiasm) in space, and knowing many, many people and organizations in its industry, I think that the main problem with the progress of the space sector is linked to the "I want it now" or "social shortsightedness" syndrome.
When one learns about the space industry deeper than the, shocking, flabbergasting, inspiring first impression, one realizes that... well, it's kind of boring, slow, and apparently stall.
An example: The latest ENVISAT satellite, state-of-the-art earth observation satellite by ESA, took 8 years to develop.
8 loooong years.
How do you sell that?
People want "hey, let's go to mars! But man, I want to see a manned spaceship going like now!".
Then comes phases A, B, C, and D... totalling some 10 to 15 years in preparations.
People lose interest.
Now try to imagine selling the ---EXCITING--- terraforming of Mars. WOW!!
Just wait some 400 years and we may be able to have something green over there! Wow, you mean just like earth? No sir, that's 400 years more.
And I haven't mentioned money yet

Anyway, I think it's more a social problem than a technological problem. We - as the human race - don't have perseverance to embark in projects that last many times longer than our expected lifespan.
Heck, politicians won't embark in projects that are longer than 4 years!
Many scientists theorize, write papers, research on subjects that are bound to be finally proven (or not) many centuries after they are dead. THAT, gentlemen, is the spirit.
Make people realize that the greater good is something that takes quite a loooong time to accomplish... (and that doesn't only apply for space), and you'll have progress. Slow, steady progress (which doesn't impede for the geniality of a few to make giant leaps forward) that will get us where we want to go much faster.
And remember, Space Whines are best served cold (near 0 degrees Kelvin), in complete vacuum, and with a touch of microgravity.

Enjoy.
Daniel