Or you've changed focus.
I look at my old code from 10 years ago and on a line-by-line aesthetic basis, it's pretty good. It's probably better than the code I wrote yesterday, given that I haven't yet setup my IDE to reformat it into a consistent style...
But that's exactly what's changed in the last 10 years. Now I consider my code in the context of the world around it, and don't waste time doing things that I can get machines (or other people) to do for me. So while my actual code has gotten worse, I'm much more inclined to use third-party libraries and frameworks when appropriate to solve problems. The problems I solve are more important to me. I pay more attention to how the code fits into the rest of the world around me than how it looks inside.