>>279706043Tadayoshi may have also just believed that he would be unable to hold on to power. And I think he'd have been right about that. Takauji was definitely more popular and respected and even he had to give a lot of concessions to his vassals to keep them loyal. And the southern court was technically still around as something for anyone opposing the shogunate to rally around. If Tadayoshi took over, there's a decent chance that Ashikaga rule would have imploded.
It's better to be second in command over the winning side than in charge of the losing side.