Yes. But at this point in time, no one is looking at a river or valley and using the noun “cradle” to categorize it. I’m not saying it could never become a lite

Yes. But at this point in time, no one is looking at a river or valley and using the noun “cradle” to categorize it. I’m not saying it could never become a literalism—only that it remains metaphorical, as a way to invoke the idea of a birthplace.