Humans being who they are, there's still a tremendous amount of work to do in this world (and beyond).

Does everyone alive already have the best quality of life imaginable, not to mention future generations?

Lump of Labor fallacy: https://en.wikipedia.org/wiki/Lump_of_labour_fallacy

Comparative Advantage: https://en.wikipedia.org/wiki/Comparative_advantage

*The key challenge* we all share is making the transition as smooth as possible for everyone involved.