I think you could actually look at this via the OPPOSITE lense: OpenSource was good for companies before, because they got free code/bugfix/labor, which would have been expensive to produce themselves.
Now with LLM and agentic factories pumping out bugfixes/code, does the equation on opensource still look attractive to a for-profit company? Why give away that sweet source code?
AI is definitely going to cause a chilling effect for (human-written) code. Why connect with other young nerds to make something cool when an AI can make it for you? Why share code if you've never sought out shared code yourself?
Further contribution to the trend of humans becoming more capable but less social.