From https://academic.oup.com/pnasnexus/article/3/9/pgae400/7754871 (emphasis by me):

Large language models (LLMs) are a potential substitute for human-generated data and knowledge resources. This substitution, however, can present a significant problem for the training data needed to develop future models if it leads to a reduction of human-generated content.
[…]
In addition, we find significant declines in posting by users of all experience levels, from novice to expert. These results suggest that ChatGPT is displacing various Stack Overflow posts, including high-quality content.

(This is just from a superficial reading of the article)

Idiocracy ante portas 😉