In 2015, the Snapdragon 801 was a smart decision. Because it was a widespread platform with many phones and there were no signs of obsolescence at this time.
The turnaround happened in August 2016 when Android 7 was released and the Snapdragon 801 was excluded. At that time, Fairphone should have started to develop a Fairphone 2 with a new chipset (Fairphone 2.1) instead of hoping to get Android 7 anyways on it with Google’s sake. Because when Android 7 is really not possible on Fairphone 2, we have a big sustainability problem which could have been avoided for the newer portion. Other way round (two Fairphone 2 versions, both with Android 7 possible) would only be a little problem (little more developing work because of two different chipsets).