Earlier quoted context omitted.
Why would he start sending patches for them? He already benefits from BBR himself. He doesn’t need to lift everyone else to enjoy the benefits, unlike the IPv4 to IPv6 transition.
And I benefit from driving on the sidewalk, why should I have to care how my car interacts with those tcp-using pedestrians? If you break TCP, and your answer is that "we'd be ok if every system switched to it", then you'd better start working on switching every system.
You analogy doesn't work, because there is nothing pedestrians can do to counter cars driving on the sidewalk. But there is a counter to TCP BBR--adopting TCP BBR yourself.