Not to mention the fact that this graph represents the situation where the considered system is under active maintanance.

The situation with Nokia & Harmattan is unfortunately worse, as the responsible people have left the house, and I assume that all r&d infrastructure has been dismantled.

Consider this:

• The source code may not be available in any usable form; even if it is stored in some repository the meaningful way to build it into packages may be lost
• The toolchains and EE (Engineering Environment) is propably lost, has been dismantled and is no longer recoverable
• The automatic test environment (servers, scripts, test cases, etc) has been dismantled and is no longer recoverable
• all the other things I cannot even imagine

In pure mathematics there never exists statistical propabilities that equal zero, only propabilities that get infinitely closer and closer to zero. On that context, chances of Nokia delivering bug fixes is far from zero, really much better than chances of the sun becoming nova tomorrow but I would not hold my breath waiting for it