I think the low hanging fruit is gone, and now innovations, mostly incremental, occur almost entirely on the edges. They aren’t creating entirely new paths or branches.
I was discussing this the other day with someone who believed warp speed travel would someday be solved, and mankind would ultimately spread to the stars. I disagreed. Just because we can imagine something, it doesn’t mean it’s achievable.
Consider “green” energy. Many seem to believe batteries will always get substantially better, and solar and wind will provide all the energy we need. While we can make improvements, full, bright sunlight only produces so many Watts per square meter. Wishful thinking won’t change that. There’s also only so much energy in wind.
“I disagreed. Just because we can imagine something, it doesn’t mean it’s achievable.”
I disagree with you on this. So did Albert Einstein. Here’s a quote attributed to him on imagination:
“Logic will get you from A to B. Imagination will take you everywhere.”
Another one is: Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.