FWIW -- I'm not worried about a path forward. Hopefully MIS is doing fine, but there are a lot of options.
Like everyone else, I try to use the "best" (lots of varying definitions here), most efficient & affordable inputs I can -- cameras, inks, papers, ... whatever. I am obviously not opposed to buying inks from different sources, Canon and Epson included. For now, and probably for some years to come, I expect "Eboni" carbon will be in the mix. However, for DIY, high end, low cost B&W, I suspect the Epson EcoTank carbon black sets the baseline. It's one of the readily available suppliers of carbon now, and for cheap. That plus my generic base keeps the cost of truly archival carbon ink so low it's just irrelevant -- not a serious factor in what I do. It's just a bit warmer than I'd like, but with my "Eboni Variable Tone" approach, it's easy to deal with.
Carbon pigments have been around a few thousand years. I think they'll be around for at least as long as inkjet printing is. I do not expect a time when I can't do what I do. I have no plans to use other than the current "Eboni," but there are lots of options.
Much more of an issue with me currently is whether to take the toned carbon approach to glossy, including particularly glossy canvas. Epson claims its glossy canvas needs no coating (sadly still not water proof, however). I, frankly, love the matte canvas (no reflections), but if real world display is going to require either a heavy coating or acrylic, I may have to explore the glossy canvas options. The market and my outlets will have some influence on that.
As an aside, to better understand my pursuit of canvas, Google "canvas display" and check out the Google images. There are a lot of interesting options to displaying canvas. Anyone with roll paper capability can build up multi-print displays -- like contemporary versions of the "triptych" -- with canvas wrap type individual displays.
Exploring the options here looks very promising to me for large image display. The point is to get our images on the wall in a way that looks the best, is cheap and fast. I think canvas wins. (So does Costco, apparently ...)
"Carbon on canvas," that's the B&W printing road I'm going down for the next few years. I'm not particularly worried about supplies.
(BTW, check out my current "Moon, Clouds, & Jupiter" image on my web page, below. I took the shot this week, hand held, with the Sony a7rii and a 135mm lens at f/4.5. I did re-take Jupiter the next night with a tripod because I wanted the moons of Jupiter to show. The hand held shot was fine for the detail of the moon, but the moons of Jupiter needed a lower iso and longer exposure. So, when I print this on a large canvas people will be able to walk up and inspect the moon. Then they might be drawn to Jupiter and -- surprise -- hopefully be treated to a view of three moons of Jupiter. You got to love what technology has brought to us photographers!)
Paul