The goal of a hobby is to have fun. If it's not fun, then stop doing it. Start doing something else. Dont think of it to same way you would a career.
So don't look at your ex-hobbies as failures, or things you didn't master, but rather as things you enjoyed for a season. They're not a marriage "in sickness and in health".
Yes, some are productive, some are not. But the-producing- should not be the point. The journey is all that matters.
Feel free to sell all the junk in your garage. Or better yet pass it on to someone who's interested themselves. That guitar I don't play anymore us someone's dream Christmas gift. And when they're done either it, they can pass it on too.