There have only been about a half dozen genuinely important events in the four-billion-year saga of life on Earth: single-celled life, multicelled life, differentiation into plants and animals, movement of animals from water to land, and the advent of mammals and consciousness.
I suppose that every time there is difficulty. I remember about Space Mountain: It took us ten years before we found the technology that would allow such a ride. And during these ten years, I had a model that I kept, waiting for the technology we needed.