We both had and have the technology.
By now we should have almost all of our electrical power generated in space with simple, proven, steam generators.
Gerard K. O'Neill wrote about the colonization of space his in his book, "The High Frontier", which, thanks to a joint effort of the Space Studies Institute and the Space Frontier Foundation is still in print and available on Amazon.
Yep.
But..but...
We have problems we need to take care of like poverty and starvation right here at home where the money would be better spent.
We have to address the needs of the poor.
We're going to pour billions trillions of dollars down the poverty rathole creating the worlds fattest bunch of poor people, blame the b@tards we're looting to do it, and pi$$ the money for space exploration away kissing the arses of the one group of people on the planet who have sworn to destroy us--oh! and buying votes!
Well, that's closer, anyway.
Our stagnation in this regard is a missed opportunity.