I used to love to untangle chains when I was a child. I had thin, busy fingers, and I never gave up. Perhaps there was a psychiatric component to my concentration but like much of my psychic damage, this worked to everyone's advantage.
I truly don't know why it was ended, though. It was suddenly decided that that would be it. They never said particularly why, because they were cut off in their prime.
When I broke in, in 1957, it was wide open. Now you're up against strong competition.