I've never understood the big deal when a language gradually dies out - insisting on keeping it around is insisting on keeping a group of people stuck in an older culture that doesn't work if they want to interact with others in the modern world.
I don't entirely disagree with you either. There is a lot to be said for joining the modern world. But I'd like to see people recording what they can of their traditional culture as they do it.
We'd all like to see a lot of things. It's unfortunate when things are forever lost, but those things are valuable, they will be translated and kept alive. If the people who know them don't consider them valuable enough, or have not been taught/informed by their culture that they're valuable to keep, they won't do it. Keeping a culture using an isolated language doesn't help that either way.