To get paid for doing open source.
This is a plea for increased funding.
You can think of it as a job application being broadcast.
His software is clearly valued, but companies take 3rd-party dependencies for granted because they're just there and can be used for free. There are things a company can do to replenish the ecosystem: Give time or money to maintain projects they depend on.
> if the benefit in CV building and personal satisfaction are not enough, why don't you stop doing it?
I'm afraid you don't understand the basic premise:
He is not (primarily) doing open source to promote his CV.
He is (presumably) doing open source for ideology and lifestyle: because it provides a good work environment where you work on exactly what you want, provides value that scales beyond what a single company can create (but is otherwise somewhat harder to measure), and provides value to the global, general public, which is not something people with day jobs can claim as easily.