I really don't want to get in the middle of this thread, but it just seems amazing to me that people think the customer is the "gatekeeper" of basic quality. If we're talking about subject matter, sure. Some people love books that offend other people, for example, and it's a great thing if they can get what interests them. But if we're talking about baseline structure, grammar, and generic quality assessments, what other business has no quality control whatsoever before the customer gets the product?
If you walked into a supermarket, and some of the food was magnificent and fresh and some of it was putrid and rotten, would you leave with a good impression of that establishment? Would you rate it solely on the quality of the best of its products? If you carelessly bought some of the rotten products, can you honestly say it wouldn't affect your opinion of the store, whether they let you return it or not? Would you have a good reaction to a manager telling you that you had the option to look at everything and choose what to buy? Readers are customers too, and they should be treated as such. They deserve to be treated as such.
It's a great, noble sentiment to assume that everyone will put in the effort to make sure their books meet a minimal base level of basic quality, but it's just not true.
I'll say this to be honest, knowing full well it will send a lot of people to the barn for pitchforks, but I've bought a bunch of self-published books, and some are excellent...but others have an amateurish and poor quality. My general subconscious reaction is to be more careful buying a self-pubbed book, simply because I have bought quite a few that I feel are below professional standards. Yes, I've read others that were great...and lots of trad published books that I didn't end up liking much. I'll say flat out that the best of self-pubbed books are every bit as good as the best of trad pubbed books...possibly even better since there is more freedom on subject matter. But it is equally true that the worst of self-pubbed books are worse than the worst of trad pubbed.
I have many reviews on my own books that say something like, "very clean for a self-published book." That is NOT good for this industry.
I'm not suggesting anything specific, but this whole area is a huge blindspot among people in self-publishing. When a group gets to the point where it can't examine its shortfalls as well as its successes, that is a danger sign. When the first impulse when hearing someone discussing potential problems within an industry is a mob attack that brings the site's moderator on here 3 or 4 times to scold people, that does not bode well for the future.
We are all getting a chance to watch publishers misunderstand change and ignore their own weaknesses. There seems to be an urge to attempt to copy those mistakes on the part of self-publishers.
Merely suggesting that poor quality self-pubbed books can tarnish the entire industry is not an attack on anyone, and certainly not on those who make an effort to produce good work. Beating up on someone for suggesting that this could hurt the industry long term (whether that proves to be right or not) is not productive in any way.