Honestly if you do a really good quality picture or comic book or so, then you could sell them at a high enough price to be able to gain a decent amount, if not a lot, of money to cover what you would normally do at the lower quality. To add to it, you will be able to get a lot more money from selling the really good, high quality art, than if you were to mass produce the lower quality art.
Although the good art might sell well, if you sell a comic, having both good art and a good story will give you a great amount of money, rather than just, amazing art and not so good story or vice versa.
I think that if you want to sell more art, then you should try to find the balance between really good art and the lower quality art. This should be able to give you the ability to keep the level of quality you want while still being easy to mass produce the art for selling.
Well I hope this helps.