Errr.. are you saying that Linux contributors are only affiliated to small companies or volunteers? Well, last time I checked, some contributors were RedHat(IBM) and Microsoft employees ;)
I am saying that big company funding of some FOSS is exceptional compared to the economy at large. Most public goods are not funded by bug companies. They do not do the same for roads or public health services, or free education or public libraries etc.
Even with FOSS few projects get the funding or contributions the Linux kernel does.