See the one thing that I'll always maintain is that the essence of the stories that exist have never left the Final Fantasy franchise after XII. And what I mean by that, is... If we were to lay out the entire scenario of the FFXIII trilogy, line up the other FF scenarios and compare them together, they really don't seem all that different from one another. Same with FFXV, actually especially FFXV. So when I hear people say that the FF franchise is dead, I disagree.
I actually like the FFXIII trilogy, I remember being pretty hype for it and I still own my PS3 copy from back in the day. But I agree completely with what you said, the execution just wasn't there and it really did a number on the story as a whole. It doesn't help that a ton of the lore is in the Datalog, and not explained on-screen, so you have to sit and read a lot of what's going on in order to really get it. FFXV didn't even have a datalog at all at launch, so a lot of it was reading random articles around the world, trying to piece things together given the context of the plot, and interviews/Ultimania/DLC.
I love FFXV (I even bought my PS4 specifically for XV and KH3), and Noctis became my favorite FF protagonist, but I feel like if they were able to nail the scenario and flesh out Luna way more, XV would've been seen as one of the strongest entries in the franchise. The lore and everything that encompasses XV could've been turned into a masterpiece if done correctly, but it missed the mark. Ah well.