I agree with you that serious issues such as depression should not be handled lightly.
Even though artists somehow owe themselves to an audience and are supposed to produced something that their audiece will accept and ask for more, there is a certain artistic freedom that cannot be threatened (and it has been iterally now that the word troll has become fashionable).
Fans want writers to write what they want, not what should be or what the writers had initially coceived.
We saw it with Game of Thrones and it has been the case with every big movie or show in the last year.
I think that some issues are so serious that they cannot be made into happy endings without insulting people's intelligence and suffering.