True...but they still have to process ALL applications even if it only to decline them. By your reasoning they will never get to decline/assess the lower scoring applications if new and stronger applications keeps being submitted. So, logically, they MUST be working off some kind of time line. So yes, you cant really go by how fast other peoples applications are being processed....but this is the only guideline to work by...by checking others peoples timelines and drawing your own conclusions.
Some applications I have seen has changed to "Application in Process" in June 2013 and their sponsors was only interviewed in Nov 2013...probably depends from case to case.
All in all, I believe that all the 2014 Applications will be processed by June 2015. That is why they stopped taking in applications August 2014. Be positive, Hope, pray, keeping faith - this is all we can do