Ok - so maybe I need to update my impressions from early MSFS2020. As far as I know, P3D, XP11, et al are actually used for logging FTD time, and the developers of DCS also cater to military clients.
I don’t know about you, but last time I flew an aircraft in DCS (MiG-21 Bis, A-10C, F-18C), I needed to manage its engines, the fluids inside, the electrical systems, the pressure, et al. The aircraft reacted realistically to flight inputs and extreme AoA, and you could tell that nearly everything inside the aircraft was modelled. To my knowledge, the radar and munitions in the game were among the most accurately simulated in the world. Now that I think about it, I don’t actually recall ever stalling my engine in any aircraft in MSFS-2020. I also don’t recall getting wing icing, or needing to use carb heat. I did need to do that in FlightGear though. A free open-source sim that has survived from the late 90s.
So perhaps you could elaborate in what you mean when you say that they are “really bad” compared to MSFS. I don’t know about you, but the only things I have seen announced about the DC-6 pertain to the aircraft model, which means almost nothing in terms of realism.