It isn't about making enjoyable monochrome games, its all about how the artist wanted to interpret the universe that he/she has created.
The artist believes that the world should go under the "Monochrome" theme, because it simply fits his/her message that the artist tries to convey.
A "Developer" exist to create games for the sake of the customers, while an "Artist" create games to express themselves.
It is not about how many people enjoy the game, it is about the people who enjoys the artist's creation.
Artists does not exist to satisfy their fans, but to create products of their expression.
that is why an artist is never rich!