As much as I wish that would be the case (I already own all of them, but I'm one of those people who just want to see people giving Dark Souls a try), one of the biggest obstacles to that thought is the fact that those games don't really see PC as a priority platform, and it's fairly unlikely for Bandai Namco to say yes to that kind of deal. (Hell, I just realised - is there even a single Bandai Namco game on Epic?).

Not to mention the trilogy is sitting in a rather awkward technical position; if they did decide to give away the trilogy, would it feature the original Dark Souls (which is unplayable), or would it be Dark Souls Remastered (which is the latest of all the Dark Souls games, and thus is almost as expensive as Dark Souls III)?

P. S. Sony owns Demons' Souls property, and there's no indication that it will ever come to PC, so that's not an option, either.