Curious if the layoffs factor in to the decline in a statistically significant way? I wouldn’t expect that to account for all of the changes but maybe that accounts for some.
Even if you aren't explicitly targeting people who's primary job is that some still likely get laid off. Sheer numbers alone could lead to real damage there.
On the other hand, if I were laid off, I'd pretty quickly clean up my open source profile and get to creating some cool open source packages to showcase my work.
Though my intuition tells me that the net effect of layoffs is still negative.
If you were coding because that's your passion, yeah. I'll bet a number of the people laid off (as happened after the dot-com crash) decided that this was the sign they should go and get a career they actually enjoyed.
Shopify as an example is heavily involved in open source (mostly Rails) and had large layoffs. I wouldn't be surprised if many of the contributors were gone dark.