I think on some level you cant make yourself feel bad for being a jack of all trades, and you can setup methods to reinforce going back to the well of whatever you were working on.
One of my compatriots who does this has a dedicated but somewhat more closed off friend who doesn't look around for new things. They challenge each other to see who can accomplish the most in some specific language, style, whatever . The flighty but open one now is challenged by someone who is more dedicated to the task, and as they keep it light hearted. Together they make some interesting stuff and are a pretty good team.