It's a really small segment. It's misleading to think that, say, if Leica can sell 30.000 cameras at $7500, then the segment must be so big that it should be possible to sell, say, 120.000 cameras at $2500 (figuratively speaking). Leica is a luxury goods company; many of their buyers don't look at the price. In that segment nobody really competes with Leica at all, which is why the company is still alive. If you are a luxury goods company in the world of the 2010s, you are effectively betting that somewhere in the world the income distribution is unequal enough, while the overall income base is wide enough, that there will be enough people indulging in luxury spending. Currently that seems to be East Asia; ten years from now it might be Europe again. I don't see Cosina in that market at all.
In fact if Cosina made a digital rangefinder, I wouldn't expect them to sell more than those 30,000 cameras, even if they make a full-frame rangefinder for half of what Leica charges for it. How may film Bessas did they sell, overall? I'd assume a number in the low five digits (but I'm happy to stand corrected if someone actually knows). That only worked out because the R&D for the camera was basically done, except the rangefinder mechanism. On the other hand, I'm surprised that Fuji sold only 70,000 X100 cameras (I would have expected it to be more). Fuji was prudent to build a mass-market-compatible autofocus compact with a movie mode, instead of, say, a manual-focus rangefinder, which wouldn't have sold anywhere near as many. Even those 70,000 were sold largely because of its looks, where Cosina for all their merits traditionally aren't strong - the Bessas are not examples of industrial design, they are very plain and functionally OK cameras built to a price.
The R-D1 you mention was many things, but it was not a great success, nor an outstanding piece of industrial design. People complained about the $3000 price, but at that price it was already difficult to provide good service, the dealer network was spotty, there was no advertising, and R-D1 sales (here I'm speculating) probably didn't generate the extra R&D millions to warrant continued development of an R-D2. The R-D1 experience was not a good one, a bold move that didn't really work out.
The digital camera market is murderous. Places like the mirrorless market are no place for newcomers - can you name any single company that makes mirrorless cameras that hasn't been around all the time with their own digital camera brand for at least ten years? The only place for newcomers are the really crazy market niches (Lytro comes to mind) and for that, well-designed rangefinder-style retro cameras aren't crazy enough. Also, digital camera turnover is short; if you have a product, you can't really capitalize on it for more than 2-3 years before you have to come out with the next one. The R-D1 was dropped three years after introduction. Leica's position is already precarious enough; if they make one camera now that really tanks after sinking tens of R&D millions into it, Leica is basically bust. Leica goes into the mirrorless market now, but their market segment is the very-high-end and the luxury market; I'd be surprised if they made anything else than a very high-end, very expensive mirrorless.
Most prominently, Cosina is now in the very comfortable position. Camera-wise they have always been a low-end manufacturer, but now, as one of the last manufacturers of film cameras, they have a respectable brand that they never had before. Nowadays, film cameras are a rewarding sector, where R&D can be done with minimal investment if you already have your assembly line and in-house know-how, and where you can expect to keep selling a successful camera with minor modifications for ten years. Why would they trade that for the shark tank that is the lower medium digital camera market? I think that's where you are too dismissive of what you call "keep quiet I don't like change" responses; actually what I think those people mean (me included) is that it works very well for the company as it is, and they have little to gain and a lot to lose from jumping on the bandwagon of a highly competitive market with short product cycles.
Pretty much the only digital development I could see from Cosina is if someone at the company makes an in-house effort with their established SLR chassis and makes a version of it that has a platform for dropping a relatively low-cost sensor and electronics roughly in the place where the film went. That would open the way for producing the same electromechanical SLRs and rangefinders that Cosina has always been making, but with an affordable sensor in place of the film on an adapted platform. Think of an APS-sensor camera with classic SLR styling, like the Bessaflex series they had, where those old lenses actually work drop-in style. Spec-wise this would be a relatively low-end camera, the selling point would be classic lenses and operation; in other words another niche camera. What would kill it is probably low production numbers, though, and competition with the used digital camera market. That's why I doubt it will happen, because that market is full of capricious people that won't pay $1500 for a new crop-sensor, low-end camera if they can stick the same lens on a used 5D or Pentax and just live with the minor inconveniences like stop-down metering.
So if Cosina does build a digital camera, it will be for somebody else.
