For me, I'm perhaps a bit burned out on FPS games in general but BF1 certainly doesn't have the staying power like BF4 did and the main catalyst for this is sheer content available I think. I departed BF4 when you had over 30 maps, tons of guns/attachments and lots of vehicle variety plus gadgets. With BF1; it was back to square one with just core maps, bog-standard vehicles and underwhelming weaponary. The lack of variety in the guns and other material just made everything seem a bit bland and with just a few maps available; you could see everything available in a short period of time. BF4 is still a complete package and gets a decent regular player count. I love the WW1 setting in BF1 but it doesn't have the scope or style of modern games like BF4.
I do think Battlefield 1 is a good game and will improve down the line but it just doesn't appeal right now and I may skip the premium pass if I don't feel like going back - that being the only thing that can really turn it around. The mechanics are great, the combat is fine, the maps are brilliant and it's visually remarkable at times but it just doesn't feel enough for me right now and I'd say its a combo of FPS burnout and a lack of content. The other factor is that there is always something else I want to play.
At least it's not pure garbage like Call of Duty is now where even the remastered is dead in the water.