I'd say that the largest amount of human involvement was on the original works of art that these models ingurgitated. What came after is only statistical interpolation.
As for the authors of the training data, they still enjoy the copyrights over the works they created. Images generated by DALL-E only copy the style, something humans are also allowed to do. Anyway, you can't put the toothpaste back in the tube, now we have to live with image and text models. Next year we'll be shocked at video models that can play games, accomplish meaningful office work and also generate long videos.
Given the court ruling I linked earlier OpenAI almost definitely does not have ownership over the output of the AI, which is what they claim.