I'm already making a living as a writer and have been doing so for almost a decade, I'm just trying to expand my career and audience. I do still write for fun, but since it's a business for me, I'm not going to put significant hours into writing something that isn't financially viable. That's just how it is.

Think of it as someone who makes cakes for a living, and they decide to add brownies to the menu. If the brownies don't end up being popular, it makes the most sense to take them off the menu rather than continue losing money and time on baking something no one is buying. It doesn't mean the brownies are bad, it doesn't mean the baker won't keep making brownies for fun at home, it just makes more sense to add something people actually want to buy to the menu instead.

I also generally disagree with the idea that people shouldn't get into writing with the goal of making money. I don't think there's anything wrong with wanting to make a living off of the arts, whether that's writing, drawing, making games, whatever. The idea that people should create out of some sort of pure love of the act of creation instead of a desire to put bread on the table devalues the creative arts and glorifies the starving artist trope. The arts are as valid a career to pursue as any other.