A few months ago a professor from the math department of FU Berlin filed a few bugs to poppler and Okular about video playing not being totally implemented/bug free.
After a few mail exchanges it became clear that given the always scarce resources in free software projects his bugs would not be fixed/implemented in a timely way since the poppler/Okular priorities and his' did not align.
Then the unexpected occurred, instead of complaining or giving up, he said "Well, i have a little money around" and I promptly suggested a few third party companies/individuals that would be interested in doing paid development and voilà! some time after, those features were developed
One of the often overlooked features of Free Software is the non existent vendor lock-in, in the non-free software world, if the company creating the software you use thinks your feature is nice to have but not important enough to develop, you are out of luck, it'll never happen, in the Free Software world you can have someone else develop it for you and get it merged upstream relatively easily.