It took 8 years from Kennedy's speech in 1961 to a human on the moon in 1969. Not only did NASA get a moon rocket designed, tested, and launched in that time, it also got an intermediate rocket program (Gemini) designed, tested, and launched prior to the moon program.
Now we're looking at (maybe) 11 years to develop a working rocket to go to an asteroid. Oh boy, journey to an, umm, space rock. Really stirs the heart, doesn't it? And this after willingly withdrawing from manned spaceflight capacity altogether for at least six years, and counting. Yep, just folding the cards and walking away from the table.
Sure, go ahead and tell me how technically challenging the space rock odyssey will be. But the call of space comes from the same place the call of the sea arose from in the past. To Terra Incognita, where "Here Be Dragons." Sorry, there be no dragons around the space rock.
The technical wizardry missions could and should be handled by robots. Humans should be reserved for missions which stir the soul, or the people who pay for such things (you and me) will stop paying.
It's hard to think of a better demonstration of how the US used to get things done, and how it does things now, than to compare the space program we had 50 years ago to the current version.
"If you want to build a ship, don't drum up people together to collect wood, and don't assign them tasks and work, but rather teach them to long for the endless immensity of the sea." - Antoine de Saint-Exupery