Back in May of this year, it was announced Image Comics would distribute all their individual comics/floppies via Lunar Distribution. This was a hit for Diamond but their trade paperbacks (a significant source of sales for Image) would still be distributed to bookstores by Diamond while could do wholesale of the comics--a slight saving grace for Diamond as it continued to hemorrhage publishers. Well, that's no longer the case as Simon & Schuster shall now get all of Image's graphic novels to bookstores. Ouch, that's gotta sting for Diamond as they now will only help with Image's distribution outside America (for now).
It is strange to think as recently as 2019 Diamond was the sole distributor of floppy comics and had a significant market presence in regard to distributing graphic novels. Then in 2020 at the height of COVID, we saw DC partner with the newly-formed Lunar. After that it was a bunch of dominos up to the present day as DC later become solely aligned with Lunar, Marvel partnered with Penguin Random House, and other publishers joined exclusively with Lunar & PRH (or partnered with multiple distributors) leaving Diamond taking a lot of hits. For years upon years, comic stores expressed to customers/online/to anyone who'd listen how much they hated dealing with Diamond and wished there were better options. There was trepidation as Lunar and PRH entered the scene, but now the market is quite diversified and it is doing great things for everyone...except Diamond, of course.
Diamond most likely will never totally fold. They still have some exclusive publishers, can distribute other stuff wholesale, and sell a lot of other collectible items to stores (toys, Funko Pops, board games, and the like). However, it wouldn't surprise me to see Diamond have to downsize operations more and more as they see their influence in the market shrink. It's been a rough three years for Diamond.