There is plenty to think about in the above responses. I'll just add a couple of thoughts. First off, you might indeed be becoming more-critical in how you evaluate your photos. Second, perhaps you could shoot more photos and "work the scenes" you encounter, as a way to go from initial experience, to a good vision of the scene, to final and satisfying shots of the scene. Maybe you are rushing things, or not fully coming to the best-possible set-ups and compositions?
Third, and this is something that comes with experience and time, perhaps you've over-complicated your gear and lens set to the point that you have too many lenses, or you've acquired a very wide-angle zoom that makes everything look small,boring,and far-away. I mean that seriously; perhaps years ago, you used a simple lens set, or jut one or two longer focal length lenses, and your photos had more impact. I personally think that is one wants to make more-impactful landscape and travel shots, the 14-24mm zoom needs to be kept in the bag, and the 24-70 or 70-200mm zooms need to be used much,much more-often.
I find wide-angle travel shots to be boring,many times, especially if the scene is deeper than 30 or 40 meters. What a very short focal length lens "sees" is often...pretty boring once the shot is back at the computer.
Is it possible that, in earlier years, you had less equipment, or simpler equipment, and that over time you've moved to high-end equipment that makes boring photos?