My taste in what I listen to has changed a lot from my early folkie days 40+ years ago, but unfortunately my ability to learn new songs has diminished significantly. This means that on the rare occasions that I sing, it is still pretty much the same old stuff, and I'm a little tired of it. Too.
I think (hope it is!) that just the part of my brain that deals with music is pretty much full.
I still enjoy singing or joining in with a roaring traddie song as much as anything, though, but only with the like-minded.
I just wish I was a good enough guitarist to play my current fancy too.