When I first watched this anime, I always wondered why the title is Kuroko no Basket instead of Kagami no Basket or any other character names in the anime. This is because Kagami is always in the spotlight. He’s the character that is improving and evolving every single match whereas Kuroko is just there to either relay information about the Generation of Miracles or to enhance Kagami’s ability even more. Kuroko really doesn’t look like the main character in the anime. So I find it quite weird for the title to be his name instead of the more prominent and influenced Kagami.
I got the answer now though. The answer is this anime really is about Kuroko. The overarching plot is about him improving and realizing his flaws ever so slowly that it took almost two seasons before he basically fully develops. All the other characters, while having their own arcs, are not as important as Kuroko’s arc.