[chrisandchris]

I'm not sure openness is the sole factor reducing support duration.

Windows 8 was released in 2012 and was supported untim 2023 and Microsoft for sure hat _a lot_ more platforms to support than Google / the Android Team.

I would argue that a closed system is a lot easier to support for a longer time (because one can mandate changes/depreciations). But for a open system, there must be another factor coming into play, may it be money or a simple "don't care".