I just don't see a massive return to the DSLR, especially in the next decade or so. Yes, DSLRs might shift to a somewhat higher percentage of the advanced camera market, but that market isn't going to get dramatically bigger anytime soon. While the majority of members on this forum clearly prefer OVFs to EVFs, many people do not, or are indifferent. A lot of early DSLR adopters wanted something digital to replace their film camera, or simply wanted something better than a point and shoot. The price they paid was not in dollars, but in size and weight. Once mirrorless cameras were comparable in quality to DSLRs, they bailed, and they are not coming back.
I'm not saying any of this to bash on Ricoh's decision to stick with DSLRs, I just want to look at this from a practical point of view. I do, however, see two areas where Ricoh could easily increase Pentax sales:
1. For the people that do prefer an OVF, but are prepared to move to mirrorless for the size and weight advantages, Pentax should release their own version of the Canon SL1. Small used to be Pentax's thing! Why can't they do it now? Like the SL1 it could largely be a parts bin camera. The two key phrases are small and light. As I said before, Pentax used to be good at the small thing, but not so good at lightweight. But I think they can do it, and I for one would very much like to see that camera.
2. Release a 35mm SLR. This one seems so incredibly obvious to me, but maybe I'm wrong? No, a new K1000 is not going to happen, and Pentax shouldn't try for that. Simply put, it would be too big of an undertaking. But something akin to a P3n or a ZX camera could easily use the shutter, mirror box, and pentaprism from the K1. All they would need to do is make sure it has a shutter speed dial, and un-cripple the lens mount, and every college film photo program in the world would buy multiples of them, and I wouldn't be surprised if a few influencers would make sure they were out of stock for a long time.
I'm sure there are other ways Ricoh could leverage the SLRs strengths, but the two I listed above are easy, and relatively low risk. They just need to make sure to stay away from bad solenoids and plastic motor gears.