How could the sales of the game be related to mechanics players didn't experienced at all about before buying it ?
The sales of the game comes from : Larian's new game + D&D new game + Baldur's Gate name. That's what the hype was about.
No one knew the deep mechanics of the game before playing it and whatever they had done, they would have sold the game the same.
They just said that it would be as close as the ruleset as possible, that's all what we knew before buying.
I don't know about you, but I read the reviews before purchasing the game. I knew it was not a 1:1 5e ruleset ahead of time, that Larian had changed things up and I was perfectly fine with it. I am sure plenty of others are too. But the major draw of interest is name recognition (and that name recognition DOES NOT just mean people that played the previous version, there are a lot of people that have just heard good things about the game). Also, people that have gotten the DoS series and like Larians game style. This is also straying from my previous reply about what MAYBE the thoughts were with WoTC and Larian to bring in a broader base to entice into getting into the D&D gaming, and why that would justify offering a more "casual friendly" introduction to possible new people.