Recently, Midnight Ink announced they would no longer publish mystery novels after 2019. This was another blow to a large number of fine authors who became orphaned.
Oak Tree Press who had published one of my books, The V V Agency, also went out of business a month ago.
Because of acquisitions, mergers and closing lines of business, sources for traditional publication of mystery novels has declined. Self publishing and existing publishers still remain options. All part of the world of publishing.