The problem with not learning languages is that it restricts you to computer-mediated communication. If you learn other languages than your own, even at a fairly basic level, there is a whole world of social interaction and culture out there that just can't be accessed with a machine in the way.

This isn't to say that automated translation is bad, I use it extensively, but not all interaction worth having is online.

The expectation is that AI translation will also become quasi-realtime, so for in-person interactions, too.

Many cultures will probably much rather interact with a foreigner speaking proficient AI translation, than a language-learner speaking with a poor accent and constant grammatical imperfections. Go to the Netherlands now as a Dutch learner who hasn't reached B2 level, for example, and local people won't like it, it just wastes their time compared to using English.