Fallout 4 is a game I never even finished the story on. As much as I admittedly enjoyed it, I eventually wrote myself into a corner on my first playthrough that would've forced me to start another faction's questline from scratch and I dreaded the thought of it.
Steam tells me that, all told, I have about 438 hours, I'd say I put about twelve to twenty of those hours into the story. Really any Bethesda game could apply here, but I can at least say I've finished the main quest to all the ones I've played--just not Fallout 4.