It's not a case of 'scew the common good', it's a case of 'the common good is better served by moving on'. In such cases, the 'more exciting' thing did not just 'come along' it was typically developed by the same people that developed the thing that it replaces. On top of that, you are still free to use the old thing.

The problem with your logic is that, in most of the cases you cite (Nokia/Digia/The Qt Company, Oracle, Canonical), these were professionals that decided to abandon certain projects/technologies.

Lastly, I don't see how anyone has the right to complain about non-commercial FOSS no longer being supported, when anyone is free to fork the old project, and the people responsible were working for free. It's just self-entitled whining.