A project can fail even if the entire development team are well-motivated geniuses with all the resources they require. A single developer can certainly be extra-ordinarily succesful and yet participate in a project that will be deemed a failure. 

When I was a young developer I soon came to realise that I couldn't let my view of my self-worth be determined by the end result of a process that I was just one small part of; I had to concentrate on doing my part of the job well, and helping my colleagues where I could.

I think the author should be very careful to distinguish between personally being successful and having a successful project. I believe the author is trying to remind us of that distinction and remind us developers that they can be proud of the work they have performed even if the project failed by any objective criteria.

But that's not quite the end of the story ...

As one is given more and more responsibility for the management of a project one becomes more and more responsible for the project's success. If one wants to take on that responsibility, they need to recognise a project failure when they see it and call it what it is. If you don't distinguish between successful projects and failed projects one can't lead their team to create more successes than failures.

As many others have posted, the success of the project is best determined by whether all parties involved (purchaser, end-users, purchaser's upper management, producers upper management, the developers, the producer's accounts department) left happy with the project.