To clarify: I find it a bit sad that humanity just isn't capable of building on pre-existing accomplishments, solutions and ideas..
What the hell are you talking about? What do you think fuels our continuing huge advancements in science, and well, everything from manufacturing technologies to medicine? Building on pre-existing accomplishments, solutions and ideas, that's what.
Sort of like the Apollo program - almost half a century after, we are not capable to go to the Moon - we simply and stupidly "forgot" how to do it. The great designers and engineers left and/or died off, and we, as humankind, went on with out collective dicks in our collective hands.
When you hear stories talking about how we lost the technology to rebuild the Saturn V rockets that were used last time, it's absurdly shortsighted to interpret that as meaning that humanity can't go to the Moon. We are sending unmanned missions there all the time; the only thing keeping manned mission from returning are other budget priorities.
Yes, we would probably have to relearn some of the manufacturing steps involved if we wanted to recreate the original rocket designs exactly, but why the hell would we want to do that? It's 50 year old technology that we no longer care about. We also can't build giant stone pyramids as well as we used to be able to, but does that stop us from building modern cities?
Take your hands out of your pants and go get an education.