Big proprietary users of protocols tend to discover bugs in them, that they feed upstream, even if they run otherwise closed networks.
E.g. it benefits you that Google uses TCP internally, even if you can't get on their network? Why? Because they've submitted patches to Linux to make it work better.
So what if they did? How are we any worse off than if they'd written their own TCP replacement from scratch to begin with?
Maybe someone outside Google gains nothing, but presumably their engineers will spend less time reinvesting the wheel, which is a net gain for humanity in less time wasted.
