You like learning new things, when they aren't new anymore they aren't fun, which is why you have a thousand hobbies that have "just been started and abandoned". Part of this is accepting that you no longer are intrigued by older hobbies, and making room for new ones. I would recommend disposing of or donating your old hobby supplies, or simply storing them out of the way in bins.
For the second part, it sounds like you don't enjoy cleaning or organizing, and are easily distracted by more enjoyable activities. A good way to go about this is to reward yourself with those things once you finish the chore or task you set yourself, rather than to switch to them immediately.
I'd also add that if you have a chore you can put off for weeks on end, it might not be that important of a chore in the first place.