Personally, the distinction I draw isn't between corporations and cooperation as per the article ("they make money" is kind of an arbitrary difference IMO), but just that in general maintainers have no obligation to do any sort of work for free.
So like, regardless of the user of the software, one should understand that there really is no warranty, or promise of quality or support from FOSS.
If one (whether it be Debian or Apple) needs a feature, bug fix, or security fix, one can ask for it, but don't expect anything.
The best way is to do it themselves, and share their code if they wish to or are obligated to under the GPL. Or commission a programmer or the maintainer to do it. Or buy a support contract from the maintainer. Or encourage it by doing micropatronage and voting for it.