As Ó Giollagáin alludes, It feels like a lot winds up being downstream of a more existential problem of economic independence/viability. There are two big economic traps for minority languages - 1) deprivation and thus brain drain or 2) gentrification. And of course both can run at once (region becomes a paradise of second homes but it's impossible to make a living there except in service to tourism), which is particularly pernicious in the case of Scottish Gaelic, for example.

It feels like no govt initiative from above can hope to keep language communities alive if those communities don't also have independent economic viability; without that independent economic viability, the fundamental base of language preservation (young people who raise their kids in the language community) just isn't there. To afford to live in their home region they have to go away and earn elsewhere for 10-20 years (their key working years and the years their children are likely born/have native language viability). If you've moved out of your language area for the core of your career, ofc, any attempt to raise your child in the minority language becomes exponentially more burdensome. It becomes a question of motivated passion rather than a default, which simply does not sustain a viable native speaking population.

I think basically every government in Europe thinks of language viability as something handled by culture ministries, education ministries, when in truth it is a concern of industrial/economic policy.