I was a newbie, and SO deleting questions didn't hurt me. If anything, they ensured that the #1 or #2 search results were exactly what I was looking for.
What benefit is it to learners if search results are full of SO threads going back and forth on the exact same topics across multiple threads?
There's a difference in finding a solution that works specifically for your case in your setup rather than finding something that is close but has to be adapted.
Sure, it's better for a new programmer to learn how to adapt solutions to fit their use case, and sometimes you will stumble across gold, but there's still a walled garden that decreases the likelihood that a new user will stay around long enough to be able to utilize the resources.
Not to mention the rampant elitism and dismissiveness of the current user base where new users are frequently spoken to rudely and condescendingly, in my experience. There is psychological punishment around every corner for incompetence even though many people try coming there in order to eliminate their incompetence.
What benefit is it to learners if search results are full of SO threads going back and forth on the exact same topics across multiple threads?