This is probably true, and while I expect productivity to go up, I also expect "FOSS maintainer burnout" to skyrocket in the coming years.
Everyone knows reading code is one-hundredth as fun as writing it, and while we have to accept some amount of reading as the "eating your vegetables" part of the job, FOSS project maintainers are often in a precarious enough position as it is re: job satisfaction. I think having to dramatically increase the proportion of reading to writing, while knowing full well that a bunch of what they are reading was created by some bozo with a CC subscription and little understanding of what they were doing, will lead to a bunch of them walking away.
Not to worry! Microslop probably has a product in the works to replace disgruntled open-source maintainers with agreeable, high-review-throughput agentic systems.
i have fun reading code, but the fun comes from knowing a human did this. if i find errors i get the satisfaction of teaching that human become a better developer by helping them realize the error and avoid it in the future. if the code is the contribution of a volunteer to a project of mine, even more so. that all goes out the window with AI generated code.