Well it looks like they want more cash from MS. They were updating on a regular basis. My guess is they got frustrated waiting for WP8.1 to come along so they could offer the full features. I blame MS over Instagram but then who knows what the issues are.
The sad part is people will tell you the 3rd party apps are better. That's not the point though.
That's because in update 1, Microsoft has adds non standard web platform features for making them thinks we're using an Android smartphone thus got a better exprience with mobile version sites. Go to Twitter for an example, you'll see a banner to install the app from Google Play Store.