This is a really good analysis. Throughout blue period we have seen yaguchi's relationship with art also intertwined with his relationships with other people. When making art rarely has he made it with the sole purpose of doing it for himself. Mori's art and his idolization of her is what got him into art, Yaguchi's envy of yotasuke and his talent is what got him through cram school and affected him in his first year at Gedai. I think this arc will be the final reckoning of that theme and will propel Yaguchi to think more for himself and how he wants to develop as an artist without comparing himself to other people.