Second, it's pretty iffy that only low-quality succeeds economically. Sure, everyone can think of examples that somehow succeed with limited merit, but you can't sustain the thesis that well-rewarded work is mediocre without ignoring a lot of strong yet widely appreciated and profitable material.
But even those two big points are minor compared to the most important one:
Everyone needs money. Even artists who do what they do for love. It's the legs of their stools you're suggesting "filtering"/kicking out too.
When someone can't earn money doing what they love, they have to spend time doing other things in order to get the money. And that's time they're not creating art and time they are not refining their craft.
What you're "filtering" out is the peak of the skill they could have developed with more time as well as the art they could have created with it. Maybe even the attention and focus they have to doing it at all, hijacked by all the ways necessity can preclude even love.
And again, for what?
A great filter, for one, that eliminates those that do art for money in favor of those that do art for the sake of doing art. Personally I don't want output from the money-motivated. I want art for art's sake. The made-for-money stuff is bland and lowest-common-denominator. It is essentially trash.