This is an under-explored question.
Preserving near extinct languages has broad support for the main reason that if a language dies, presumably some part of the associated culture dies too.
I don’t doubt that some unique culture exists in language, but what, exactly? And is it worth preserving even when considering the costs?
First, there are the opportunity costs of people encouraged or force to learn a language that’s just not that practically relevant. For all the time students in Ireland spend studying Gaelic it’s time not spent studying English, the language of the world. For all the time people in Mumbai spend having to learn that city’s new official language — Marathi — it’s not not spent studying Hindi or English. In America, the 22 children in on this Wyoming Indian reservation are being taught exclusively in Arapaho so as to preserve the language of their elders. The cultural interests of the adults come at the cost of competitiveness of their children.
Then there are the real costs of preserving a minority language in a society. The EU spends millions translating official documents and sessions all to pay due respect to cultural diversity. Canada spends an astromnomical amount translating everything into French all in the name of preserving Quebec culture.
Bottom Line: I question the assumption that preserving a near-extinct language is worth it. At the least, we need more discussion of what exactly is being saved and weigh those benefits against the costs.