Steph and Dirk lead teams to titles fine. Often title teams don't have a great defender at their shortest PG position, which is the most irrelevant position to a teams defense. Its much more critical at wings and front court positions.
Dame has played virtually his whole career with a short poor defensive SG. The Blazers main issue is they have had horrible defenders at other positions such as CJ Ant Melo Kanter. Or they've had defenders with horrible spacing in offense.
Put talented two way players all over the rotation and the team would be unlike any recent Blazers team. When Dame had Matthews at SG with his excellent defense, a roster of two way defenders, even with less than ideal Mo Williams defense and no bench, the teams defense was very good. Dame is a much better defender now than he was for those first few years, even if hes not great.