I remember when Manybooks used to be what you want. But quality dropped precipitously with self-published new novels, I suspect some money is changing hands somewhere.
What happened to Manybooks? Does Standard Books have a plan for avoiding that?
At SE we focus exclusively on US public domain titles; that's one of the major philosophical points of the project. The other major point is a high quality standard, so it's in our best interest to keep pursuing that. SE became known due to its quality standard, not because it's more free ebooks. Therefore if we strayed from those points then we'd be just another free ebook site, of which there are no shortage.
Quality is also why we reject self-published books that have been dedicated to the public domain, as those are typically low-quality content to begin with. (Though I wouldn't call every single book we host "high quality content" in the sense that each one is up there with Shakespeare. But books that have survived a hundred years tend to have survived because they're not slush.)
Every other book I read now is by an author with NO rating, I have read six this year, none were memorable, or my cup of tea I will give you that, but two of the four- or five-star offerings on Amazon were just as bad. As they say, if you don't open an oyster, you will never find a pearl.
That's not the niche SE has chosen to target. You can't expect them to serve every possible use case.