I can only go with the experience of my friends, who've gone both routes successfully.
It's true that traditional publishers expect mid-list authors to shoulder most of the promotion efforts these days. I never said they didn't. Fiction authors are now expected to maintain a platform, which used to be a non-fiction thing. Certainly traditional publishers have become more predatory and less supportive than they were twenty years ago. I don't have an inside track on why that is, but I suspect there are several causes. One is that POD allows publishers to make an reliable though modest profit from their mid-list authors, which ironically makes them more risk averse. But publishers still provide production and editing services on a MS that'd cost you maybe ten thousand dollars if you were contracting those services out. They also get your book in bricks-and-mortar bookstores, which is a bridge too far for most indy authors, even the successful ones.
A lot of the bad feeling that publishers get from indy authors comes from two sources. First, a long history with rejection. Second the lack of respect indy authors get relative to traditionally published authors. We can see it in this discussion elsewhere, where one poster puts "authors" in quotes when referring to indy authors. And it's easy to see why because most indy authors just aren't good enough to get traditionally published. *Some* indy authors put out a product that's every bit as good as the mid-list authors from the big publishing houses, but most just dump their terrible manuscripts on Amazon with a clip-art cover and no copy editing, much less developmental editing.
The statistic that most indy authors make their investment back plus 40% didn't impress me, because (a) that counts the author's labor as free and (b) most indy authors don't invest much cash in their projects. The percentage of indy authors that clear, say, five thousand dollars in profit are very small.
It's not that indy publishing doesn't have its points, and my traditionally published friends are certainly thinking about dipping their toe in the water. But it's not as cheap as it looks if you want a comparable product, and you give up certain things. I was in Manhattan recently and went to the 5th Avenue branch of the NYPL. My traditionally published friends' books were either on the shelves our out circulating. The NYPL had *none* of my indy author friends' books, even though at least one of them has made the New York Times best seller list.