I can see why there might be a temptation to think that TB was the reason: after all, the DOS games were huge hits and a section of the gaming community was (and still is, to some extent) extremely vocal about it all being due to turn-based because harking back to The Golden Age Of Video Games™ etc and so on. They sold because they were good, and speaking personally, in spite of them being turn-based rather than because of it. Which is as subjective an opinion as anyone's, in addition to not being any better at any other form of combat nor tactics, but I play RPGs to, well, role-play rather than it just being about fighting and strategy.
I agree with this and have been saying this myself. I'm quite convinced the most important (though obviously not only) reason for the sales figures of D:OS2 is co-op play and DM mode. But, again as you say as well, fans of TB combat are extremely loud, aggressive and in your face in terms of pushing their preference over others' preferences and selfishly demanding on every forum that every single game should be TB. So that's why the debates end up becoming focused on whether the combat system will be TB.
