If it is open source, as in a Debian release, an end user's recourse is to fix it themselves.
If it is commercial, be it closed source or not, an end user's recourse is to sue the supplier (or something similar).
The commercial supplier has a financial incentive to get it right, the open source developer has an intellectual and street cred incentive to get it right. I'm not sure which one actually works better, I know that the popular opinion is the ESR eyeballs claim but it's not clear to me which gets it more correct. Seems like they both fail at times.