Dear Abdul, excellent post..! I suspect that one reason could be be that many project managers (and those they work for) think project termination is project failure. And project statistics quoted by such bodies as the Standish Group usually paint a bleak picture of the state of project management implying that cancelled projects are failures and often due to poor software project management. Barry Boehm of the University of California, Computer Science Department, suggests that this is a false impression in his article, "Project Termination Doesn't Equate Project Failure." Nonetheless, most folks think project termination is project failure and I have never seen "Project Termination" skills, experience, and leadership on a resume.
I suspect that another reason could be that often times project managers are told by management what the project due date and budget is upfront, before any real, detailed, project planning (scheduling, risk management) has taken place. And when the project manager reports the project status, issues, and suggests rebaselining the project (budget, schedule, etc.), that someone else that you mentioned (Finance Director or the MD) that must make these decisions (change to budget, change to schedule, etc.) is usually the one that "stays pat".
In the end, when things have gone wrong for too long, plenty of blame gets spread and it quickly and always finds the project manager. But getting back to your question, "Why do some Project Managers still continue on as if nothing has happened?", I am not sure they do nor that their "continuing on" is what really is taking place. Perhaps an interesting following question to your post would be, "Who has more responsibility for failed projects continuing on? The project manager or management." My vote would be cast "management", but my past experiences and bias in favor of the project manager on this issue could be outside the norm. Great post...! I do hope we hear and learn from others. Cheers..!
Mark Perry
VP of Customer Care
BOT International