Failure in project management is also failure of the manager in charge only, no this team? yes to no.

the failure is80% of project manager and20% of the team

This failure is the result of lack of rigor

Yes. Accountability for the project's success lies only with the project manager. I see that a professional project manager should never reach this stage. He/she should predict and manage that as soon as it starts and it doesn't just happen.

projects are all about teamwork which is only managed by the manager.

project fails ...we all fail as a team.

teammates influance team members including the manager

my answer no

My answer is YES IF AND ONLY IF PM has the full authority and flexibility in all respect and is allowed to function without any external interference.

The Project Manager is solely responsible if any Failure occurs in the Project. To be very Specific here with the words i use - Failure of a Project = The End Product / Result / Service is not the same as was promised. 

Note: There could be external factors affecting pre-closure of a project. For ex, natural disaster like earthquake. OR Govt approval pending for a long time on some tenders OR Sudden Change in Regulations affecting changes to project Cost / Time. 

Project Manager is answerable to exective managment and fully responsible for success and failure. If his Team was unable to perform, this again shows that the Project Manager could not manage the team (project resoucres) well

Yes

Yes, the Project Manager is solely responsible for the failure of the project and not his team. 

No

Not always. Because success and failures are shared responsibilities. Project manager neither any one person of his team can lead to success of failure of a Project. Great PM with worst team or worst manager with great team cannot  consistent results.