Viking’s demographic has always been an older crowd.
As a laid- back experience, with no Broadway shows or climbing walls, etc., older folks tend to gravitate toward the small ship, simpler experience.
As a relatively pricey cruise, well-to-do older folks are more prevalent, and wealthy older folks tend to have more infirmities.
As for the dress, my theory is that Viking has to go further down the demographic ladder to fill their ever-expanding fleet of ships. In addition, while they publish supposed standards, they obviously don’t enforce them.
Viking has never had a diverse cross-section of travelers, which many of us are fine with.