He has a lot going on in real life and couldn't keep leading the Waste Rangers, he left it up to the members to decide if they should keep it going. A majority wanted to lay the Rangers to rest because they felt that it wouldn't be the same without Duke.
Alright man, you're partners ready to roll out, I just need one post of you entering then you'll head out with him, try to get it within the next couple of days please :)