Well, the truth is, and they actually have real data for this now because of being able to track cell phones, must people spend 95% of their existence in a 4 sq. mile area from their homes. So what would it matter for somebody that could find an enclave of people speaking their base language in a foreign country, if within that community they could find the money/accommodations to keep afloat? Especially older folk whose job prospects don't really have any chance of improving regardless. In your above scenario, you could easily find a corner of Mexico with enough white/English speaking people and not give a rat's *** about speaking the language. Ideally you would want to just to immerse yourself better, but I don't think it's necessary. The lady in that video appears to speak Urdu though, and I'm damn sure there's not a huge Hindi-Urdu clique in the Netherlands so you would think she would absolutely have to learn the language to have any semblance of a life.
It is an important issue because Western countries are killing/not having babies and their welfare ponzi schemes are going to fall apart unless the floodgates remain open. But people that don't know the language can't possibly carry that tax burden. You need immigrants that are able to climb up the ladder, not be stuck in the lower end grind.