The best sellers by "name" authors are driving the entire industry. Yes, there are best sellers, they exist, but the odds of a first-timer hitting that "hole in one" are daunting. In the publishing world first time novelists are mere cannon fodder, grist for the mill. A newly-hatched baby sea turtle faces better odds than a first time novelist.
And why should 5th Avenue care? No matter how badly or stupidly they treat first time authors, another 100 unsolicited manuscripts will arrive tomorrow.
OTOH, you have A Patriot's History to point to, which is a plus for getting your first novel published. However, that merely puts you on the shelf for 60-90 days, and as I mentioned, 19 out of 20 first-time novels end up in the returned unsold bin, and these "failed" authors don't get a chance to publish novel #2.
Doing it on my own, I've sold over 5,000, and trust me, I'm getting a lot more back than 8% royalties.
Go Travis! Go Travis! Go Travis!
I think the PHUSA network will sell September Day beyond the "lower tier" of 20,000 copies. But self publishing always remains an option.