IDC has some new forecasts that predict smartphone sales growth is likely to stall and that the respective market shares will be roughly the same in 2018 as they are now.
Four years is a long time in mobile and it’s brave of IDC to forecast that far ahead. IDC says the smartphone market is becoming saturated and the new emphasis will be to bring prices down. I personally believe iOS will see a larger erosion of market share than IDC predicts, due to very low cost Android devices. It’s unlikely Apple will try to compete at this level. However, from an app developer viewpoint I don’t think this increased market proportion for Android will have much added value. Low end users are less likely engage in activities that result in app generated revenue.
UPDATE: As several people have pointed out to me via twitter, IDC were also the research company that predicted Windows Phone would soar to no 2 by 2015.