I do agree, all the more so because I have spent a good part of my career as a researcher repeating that to all and sundry. Obviously, how useful a language is plays a role for many people.
Ultimately, the ones who learn more than the basics and retain that language, the ones who keep up their skills, will be those who find other reasons to be interested. I believe that this involves integration to some extent, a desire to communicate with members of that other group and to become like those who can speak that other language by sharing their culture.
How can we create that kind of situation? I think it is a matter of interaction between groups and mutual appreciation. There needs to be interaction in an equal and pleasant environment that will lead to positive relationships. There are some federal programs that do this. For example, programs that allow students to travel across Canada and live in a second-language setting.