They probably wouldn't continue the story from RE6 as I don't believe that title was very well received by fans. Not even Piers got mentioned in Vendetta or RE7, so it's like Capcom just moved on after his death, and acted like it's not a part of history anymore.
I agree that Capcom does a bad job of picking up the pieces of where the current story concludes. Every game is inclined to just loosely connect to things that occurred throughout the prior games, so that fans feel like it's important, when Capcom knows this isn't yet another game that is a true sequel. Even RE7, which felt like a spin off, tried to be slick by adding in newspaper articles and pictures on the wall, reminding you of the original game's location, etc. But really, it's also mostly a sequel that has the name on it to sell it. Think of how the Silent Hill games have different stories and new characters, but they didn't really link to each other, besides the third one being a proper continuation of part 1. But the rest felt like they were unrelated.