It’s OK to say “No” or “Pay me and I’ll do it right now” to companies doing this.
(And on the flipside, nothing is owed for a bugfix the maintainer made out of their own free will. Again, a gift.)
Correct, maintainers can say that and get shamed.
And it leads to unmaintained libraries, since companies don't want to pay.
At some point, is open sourcing your work a liability?
I 100% agree with this. It also is 100% OK to fork aggressively and patch yourself.