The best analogy I can think of is that it’s also challenging to reproduce the Great Pyramid now, even though it was something that was accomplished 4000 years ago.
It’s not that we don’t know how to do it, it’s that our priorities have changed. We’re not willing to spend the money it would require, and we’re not willing to take as many risks with human lives as we were then.
But we COULD do it.
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