The four reasons given for Facebook’s app failure are legitimate points, but I think a fifth reason as pointed out in the comments is definitely necessary.
Facebook might be slow as HTML5 but it’s not that bad. The biggest issue by far is the lack of caching and fetching new data in a reliable and stable way. You’ve seen the Android notice box that appears occasionally stating something failed.
But a native app will do this better, better chances for fallback, handling and looking good. So when can I expect the native Android app? I’d say right in time for the holidays.