You can convince yourself that "hardcore RPGs" only consist of titles such as Age of Decadence, Underrail, and Arcanum, but in that case you're merely engaged in circular logic ie: "hardcore RPGs don't sell well. Therefore, any game that does sell well, isn't a hardcore RPG."
We have some assumptions in this thread, assumptions that have an inner logic, but you are presenting them individually, and as loose as possible, to suit your poor argumentation. First, let’s talk about what is hardcore. “Hardcore” is a relative term. A game x is hardcore in comparison to another game y, if it’s too difficult in comparison to y. In that sense, BG2 is hardcore relatively to Skyrm, but it is popamoler in comparison to Darklands. When I talk about hardcore, what I have in mind games that are difficult in comparison to games such as BG2, Fallout, Kotor, etc. Since I don’t have half the knowledge of most old-school players here, they will probably have an even more strict conception of what is hardcore. And yeah, old-school it’s also a relative term. I’m an old-school player to a causal gamer, but not to Vault Dweller, for instance.
Secondly, we have to make a distinction between the ideal cRPGs and cRPGs in general. You can appreciate a cRPG even though he lacks some of the features you think are important. Fallout, for instance, is a great cRPG, because it has great writing, mature themes, C&C and was super innovative. However, the combat is bad, it’s too easy, and it also had some silly jokes, etc. The fact that a game I think it’s important is not hardcore should tell you that for me being hardcore is a desirable and important feature, but not the only feature that defines the quality of a cRPG. The same thing holds for other things, such as turn-based combat, good combat system, etc. You can have different combinations. Gothic 2 is hardcore, but has real-time combat, while Fallout is not hardcore, but has turn-based combat.
Thirdly, we have the subject of this thread. What people like Vault Dweller is arguing is that decent cRPGs have some features to a certain degree, and this will make them sell less in comparison to other games, especially if the feature in question is being hardcore. The list of cursed features includes complex character building, solid combat system, turn-based combat, heavy-texted writing, stat and skill checks, deep C&C, etc. Thus, what we want to know is whether decent cRPGs in general, not just hardcore cRPGs, can sell well.
Your counter-examples of decent cRPGs that sold well either involve a feature that is not properly implemented, or a game that is not really a cRPG, or a number of sales that it is not significant. For instance, your example of a turn-based game that sold well is a popamoler X-COM, but since the combat system is a joke, the turn-based is a fluffy feature.
Your example of a hardcore game that sold well are the SOUL series, but they are arcade games, not cRPGs. Players don’t have to think about allocation of stat and skill points, etc. This challenge involved in character building is what we have in mind when we talk about the hardcore feature repelling players from cRPGs.
You also argued that some games are proper cRPGs by our standards, such as Fallout and PS:T, sold thousands of copies. You think that this is an undeniable proof that proper cRPGs can sell well. But again, that number is not significant for a medium studio and they sold so much less than bad cRPGs such as Diablo. This is understandable, because Diablo doesn’t have the dialogue checks of Fallout or is heavy-texted as PS:T. People already pointed this to you, but you ignored the arguments and it’s still repeating the same thing.
We are not assuming what is at stake, you are. What you need to show is a simple thing: a game that sold like Diablo when was released (years of steam bundle doesn’t count), but it’s a proper cRPG. For instance, if you think that the popamoler XCOM is a proper cRPG and has a decent combat-system, you just have to explain to us how this is the case. Only by doing this we can advance the discussion in a meaningful way. This is not just a matter of opinion or whishful thinking of a minority of elitists. This curse is real, and it matters for fans of proper, decent cRPGs.