Wrt generation starships.... if that were possible, don't you think we'd be overrun by aliens already? If you ever tried to design a generation starship you would find that it violates several laws of physics, for example the Law of Conservation of Energy, Stefan-Boltzmann's Law, and the Ideal Gas Law, among others. These are not what you call "technological hurdles" - they cannot be solved with some new engineering trick. They are fundamental. It would only take one to prohibit interstellar travel. In fact there is a list. Bottom line is we're stuck here, in this solar system.

I would further conjecture that one of the prerequisites for the evolution of life such as ours is that interstellar travel be impossible. Otherwise, our species would be subjugated for eternity, even blasted to extinction, by wave after wave of superior aliens. In contrast a universe in which interstellar travel is impossible can support a massive variety of intelligent species, all surviving simultaneously. Perhaps to some end, perhaps not, I cannot say. Most of humanity looks to something greater than ourselves. Perhaps there is more to the universe than meets the eye, perhaps not. Time will tell.

My perspective on species survival is somewhat similar to the old "don't put all your eggs in one basket" idea. However, I combine that with the expectation that we must adapt. We have no hope of spreading life of any kind to other solar system bodies in our current hominid form - that form is evolved for the surface of Earth. We must adapt. That adaptation is more profound than you think: a world with billions of people, thousands of languages & thousands of religions, all providing enormous inertia to any large-scale scheme. Greater integration of the people will facilitate more common beliefs, but all these things take time, generations in fact.

Right now a whole solar system is the only generation starship design that works. Nature is wasteful indeed!