Are you willing? Do you want a certain feature? There's nothing stopping you from making it yourself.
A company literally makes an entire project open-source (and with major contributions from people outside that company) and you still say it's pRoPrIeTaRy??
Have you submitted any concrete requests or proposals? You want other people to magically guess exactly what you want AND spend their time and effort to make it for you, for free?
What if Apple stops development on other platforms, or makes future development proprietary who is going to maintain it for other platforms?