Well, Kathryn, it's certainly not aging. 2 years is very little in the grand scheme of things. I would say it's the other things you listed, all together. These have been 2 years that were "No fair piling on!"
Like Kathryn, journaling has seldom helped me with healthy habits - well, unless I count chatting with ya'll. I remember her ds saying she was blogging here and just didn't know it (or something like that) and that's quite true about all of us.
I do seem to be helped by minimal note-taking, and so I do well with cards/forms/charts in which I only expect a checkmark √ √ √ √ or a fill-in-the-circles count 0000. Sometimes just the briefest word, like "good" or "poor", or a workout name, or shorthand for a food if I want to note it.
I met all my healthy habits goals today. ( I know this because of my shorthand in my healthy habits page). Right now I'm hole-punching weekly pages that have columns for 7 days each, to go in a 3-ring binder. Wouldn't be surprised if I go back to cards, which I do like and which are easy to save, but this has been a good choice when I'm also recording workouts on calendar sheets that can use the binder as well.