Sometimes, there comes a point where all logical reasoning is not enough. The causes of this may include political or personality reasons (eg. ego). In such situations, leadership is called for. If a project fails or is otherwise compromised for technical reasons, the villagers with their pitchforks will hunt down the lead architect. Therefore, as such an architect, I insist on having the final word on design and will override those with dissenting opinions, if despite best efforts, consensus cannot be reached.
If hiring a lead architect for a specific project, they should have the final word on the design of that project. The only exception is if they’re overridden by more senior personnel (CTO / Chief Architect).
As we all know, ‘design by committee’ does not work. When it comes to leading, there can be only one.