First of all, thank you so much for playing!
It sounds like you've reached the end of the current content. The Expedition Team and the story after Ruby forms it are still in development, and we're working on adding more quests and story content.
As for the dragonfruit, it can definitely grow. The garden currently has quite a few different fruits, and since they spawn randomly, you may have just been unlucky and not seen one yet.
Thank you again for spending so much time with Jam Workshop and for your feedback! It really helps us improve the game.