There is an argument that making and publishing free macOS apps is a lot more "contributing to the commons" than writing C++ for Haiku that will be used by 100 people maximum.
And how is Apple ever going to change if no one makes a credible competing open solution? I believe Haiku is going to get a lot more popular with creators. Unlike Linux, no corporations control it, and it's also more Mac-like than the thing the Mac has become.
One of the biggest improvements coming to Haiku is hardware-accelerated Vulkan graphics. I am so excited for this! https://discuss.haiku-os.org/t/vulkan-lavapipe-software-rend...