I think Primmie actually can and wants to play duelist, BUT some members of Talon aren’t good enough at playing other roles, like setting up utility to create good advantages for Primmie to secure kills (as seen in previous matches). If Primmie plays duelist, it becomes very hard for him to get kills because he has to rely more on his individual skills rather than team utility. So, the result remains the same, in my opinion.
Still, remember that this team has two duelists (Ban and Governor). You can see from Ban playing other roles that he uses his gun more than his utility—I think this is a duelist mindset. The result of his play is 50/50; it entirely depends on whether he can hit his shots or not.