The state of mobile OSes does depress me. If Microsoft failed with Windows Phone I can't see how anyone else could succeed in launching a third major phone platform.
While it is going to be a tough Battle, worst than any other platform in the history of computing. I dont think Windows Phone and B2G ( Boot to Gecko ) should be used as example. Windows Phone / Microsoft clearly has an execution problem. BTG / Firefox OS had resources problem. And was focusing on $35 / $50 dollar Phone platform. ( What KaiOS is currently doing ). Both has ZERO understanding of mobile phone platform and industry. And that learning experience took a few years before they run out of patient / money / momentum.
We actually wrote an entire jvm in javascript to try to get the J2ME version of WhatsApp working. It actually did work, but not well enough to be considered polished, and I think they must have discontinued the J2ME implementation as feature phones became more and more rare.