Which is why the effort - and results - of Nokia and the Mer team are to be lauded in providing a continued mechanism for supporting out-of-date hardware in a commercially realistic way.
Even a community as active as this can't possibly juggle updates and ports between, what, five?, OS versions (Diablo/Chinook/Mer/Fremantle/Harmattan). I guess some would phase out - but aren't people still using Chinook and maybe there will still be users clinging on to Diablo after Mer comes out. It still feels like efforts would/could be spread very thin.