> someone clueless about photography just shooting hundreds of photos?

That doesn't exist. The very act of taking hundreds of photos will give anybody a clue. They won't be able to pass a written test - they will have no clue what terms like "depth of field" mean - but they will start to apply the concepts in their photos without knowing the terms.

I suppose there is someone who takes hundreds of photos without ever looking at them and thus never starts to develop any sense of what is good. Likewise some people just have more taste than others and so will get better. However in the real world people are taking lots of photos and they are on the way becoming reasonably good.

Training alone will not make you a good photographer. Someone already skilled at this can help you look at your photos and understand why it "looks bad". However it takes hundreds - perhaps thousands of photos before you become an award winning photographer in the best case. While someone without training will need thousands of even tens of thousands - but these days a photo on an iphone is cheap enough that getting a thousand photos is not hard.