It doesn't take a large team. Look at latest indie hotness Hollow Knight (https://youtu.be/UAO2urG23S4), which was made by 3 dudes, who were artists and animators (http://hollowknight.com/our-team/). I agree that with game engines, making a successful indie game is primarily about artistic prowess, but you probably don't need that many artists. Just 1 or 2 really good ones.