A super post! Thank you from a wanna-be self-published author for putting this blunt advice out there. Having said that, I greatly fear that the people who need to take this to heart most are the very ones who will blow it off. Sad, but the thing that makes self-publishing so appealing (no gatekeepers) is also what makes it possible for unprofessional yahoos to publish just as easily as dedicated writers.
Luckily, their poor covers, unedited content, and clueless attitudes will bring them down. Not so luckily, they may bring others down as well.