I frequently hear that, but in practically every other profession doing the exact same thing for 20 years is still valued. And the underlying reality is you can’t do the exact same thing for 12 years in the computer field. Experience is all the little edge cases that cropped up over time.

"Experience is all the little edge cases that cropped up over time."

Absolutely. I will be using this one.

This is not exclusive to dev work. Same can be said of managers.