Your overall point is correct though.
If not, then solve for X in "X == quality".
From the horses mouth: "The Man Booker Prize is the leading literary award in the English speaking world...” [1].
The best way to do it is probably For publishers to also publish books they think are good, even if they're prospects aren't great. Most will fail, but a few will win big. In a way, it's just like venture capital.
Maybe we need a venture publishing industry.
They already do and we already have that. In fact, that is the reason why so many authors are dissatisfied with publishers. Publishers publish a large number of titles on the hope that one of them will take off, and spend little to nothing on promoting the majority of them. So in the majority of cases, titles are neglected and may not earn back the advance - unless the author has a significant existing audience. Then they get a better deal, too.
I've spoken with professional authors and editors, and I get the impression that the typical mid-range fiction publishing house pretty much _is_ a "venture publishing" operation. They buy books from lots of authors, many of whom disappear without a trace. The bulk of their profits comes from a handful of well-known authors.
I usually don't like jumbled stream of consciousness novels, but I like this one. It reads like a really good standup comedy routine where the humor is sitting just above the surface of deeply unpleasant truth.
I'm glad a publisher finally took a chance on it.