A true cRPG has a pretty hard ceiling of no more than about 2 million in sales over the long term ... which would about match D:OS2 sales.
So you consider DOS2 a "true" cRPG? Interesting. I wouldn't have expected that.
But anyway, what makes a cRPG a "true" cRPG? And why can't a "true" cRPG break through a ceiling of 2 million sales?
You are clearly lacking in the ability to be logical. How do you get one from the other? 'True RPGs don't sell over 2 million.' 'D:OS2 sales were about that.' Two completely separate things. How does the first mean I'm saying D:OS2 is a true RPG? No logic there at all.
Saying something is a true RPG is a way of differentiating it from a new sub-genre of RPG that emerged in more recent years, namely action RPGs.