I think it was different pre-AI. Someone might come in and spend days getting some understanding of the codebase before they contribute some minor fix. Over time they might stick around a make some more of these, progressively gaining trust so when they do take on something bigger the maintainers will know they aren't wasting their time reviewing it.
Now they can drop a multi thousand line poorly understood PR day 1.
Now they can drop a multi thousand line poorly understood PR day 1.