By your definition of "true" cRPG, would you consider a cRPG not a true RPG?
And why can't a "true" cRPG break more than 2 million sales?
As has been pointed out, c just means computer, so cRPG and RPG are essentially synonymous. I just used the word "true" to signify a classic, old-school, single-player, isometric, party-based cRPG in which story, character development, branching dialog, deep quests, meaningful choices leading to meaningful consequences, etc. are the core of the game and combat is only a small part of the game. If you don't like the word "true", by all means feel free to come up with some other term. I just grow tired of constantly having to write out my definition of what I mean and so was just using a shorthand.
As for the sales ceiling, it is my conclusion based on what I perceive the market to be for the type of game I've described above. The only cRPGs that have broken that ceiling have all been action RPGs (ARPGs) (don't know about JRPGs because I don't follow those) - for example games like Skyrim, Witcher 3, and yes even DA:I which has sold well above 2 million.