How many people work full time ubpaid on the Linux kernel? For the 4.15 kernel, AMD, Intel, Google and Red Hat contributed between 35 and 50% of the changes, depending on whether you count number of commits or number of lines changed.
How long did linux exist before there was a corporate sponsored person working on the kernel?
Only half rhetorical, as I'm actually curious.
Maybe, if you extend that to free software in general. It's interesting to think about.