In my opinion, the quality of recent publications in general has declined, regardless of medium. I think that this is a result of a decline in the quality of primary and secondary education, as well as the impact of the broadcast media. People who should know better now speak television-quality English. Then, those who would write without first acquiring a solid foundation in grammar and usage begin to promulgate what they hear by writing it down.
One of the most common and grating results of this is the struggle for life of the objective case of the first person personal pronoun. You know the one I mean, don't you? The perfectly good, grammatically correct use of the word "me" is being systematically trampled by the pseudo literate, including many of those who edit traditionally published material. Nothing annoys me and other careful writers more than to see the beginning of this sentence become "other careful writers and I." I offer that as an example; investigation and proof are left to the reader.
Some make the argument that English is a living language, and that it needs to change with the times. I'm certain that it's living; I hear it scream every time somebody tortures it to make it change its behavior to accommodate laziness on the part of a would-be writer or editor. Change should be for improvement; not because of carelessness or ignorance. The results of reducing our language to its lowest form are sometimes comical, sometimes pitiful, but they rarely convey the writer's precise meaning. No matter how emphatic and engaging such works may be, carefully parsing what was written often yields ambiguous results. That's unfortunate, because written English offers the writer a degree of precision that is difficult to achieve in other forms of communication.
What does this have to do with self-published works versus traditionally published works? I have developed a preference for self-published authors over the last couple of years, for a couple of reasons. The biggest one for me is the breadth of material that's self published. There is something for every taste, for every mood. Nobody screens out works that don't have enough market appeal. Writers are free to write about what interests them without worrying about catching the attention of an agent. Does this mean that there is a lot of poorly written material available? It certainly does. Do you have to read it? No. You can download and read a substantial sample and decide for yourself whether to buy the work and invest your time in it. If the writing is atrocious, it only takes a few seconds to delete the offending file and move on. There are a lot of gems to be found in the swill, for those who take the time to look. The gems are often works that wouldn't make it through the screen of the traditional publishing industry, not because they are poorly written, but just because they have different characteristics than those that have sold well in the past.
I don't believe the traditional publishing industry is evil or nefarious in its selection process. I believe the industry is using a business model that has worked well for commodity products in the past, but which penalizes writers who don't already have a following. That's not bad; it's good business, if you are a traditional publisher. They want to publish what will sell. The weakness in this business model is that it discourages innovation. When an innovative writer comes long and builds a following, the publishing industry is there to help, except that at that point, their added value is purely in warehousing and distribution.
Attempting to justify their existence as gatekeepers for quality is a losing proposition. It didn't work for any of the recently dismantled monopolies, and it won't work in this market, either. What do you think?