What if what humanity needs is to realize that you don't have to scale to the limits of the planet for something to be worth while.
Maybe the "time better spent elsewhere" should be spent learning that we are all humans with amazing cultural backgrounds, and what could be a better way to engage with others than through language?
I've just been reading way to much history of South America recently to accept this idea, but let's be honest, the entire world is based on this concept. Every time somebody tries to setup a "Planetary Language/Religion/Culture" it comes at the expense of "the others". Fuck this idea.
Learning languages is fun, and the people you can meet (which you wouldn't otherwise) and things you learn about your own native languages is worth it to me.
I think anything that allows other people to get outside their box and learn more about (and from!) people who don't share the same cultural background is a positive for the world.
All this is lost if we all switched to Esperanto tomorrow.
What if what humanity needs to realize is that language learning is a waste of time, unless you are studying the history of language. There's no reason we shouldn't have only one planetary language, besides the whims of governments and nationalists.
I dream of a advanced designed language that incorporates the best features of existing written and verbal systems. Now that's a goal worth spending time on.