I read the paper linked here, which develops a mathematical model for language transmission and survival, using Welsh and Māori language as worked examples.

A crucial point it makes is that if Māori language teachers are spread across the whole population at present rates, te reo will die. If they are concentrated on teaching the Māori population, it will live... all other things being equal. Other things that might affect it are the age groups which are learning the language the most. The 22-44 age group seems to be the one doing the most learning right now and since that's peak child raising years, the authors think that might have synergistically good effects.

https://scholar.google.com/scholar_url?url=https://royalsocietypublishing.org/doi/pdf/10.1098/rsif.2019.0526%3Fdownload%3Dtrue&hl=en&sa=T&oi=ucasa&ct=ufr&ei=D4n7Y_HDD4KLmwGN2aygDQ&scisig=AAGBfm3tMyPFQfm__00DCKUSbxg2b3AxLA

#teReo #māoriLanguage
There is a serious question here for tangata tiriti studying te reo: are we causing harm, since we live in a community where we have fewer opportunities to spread and use it, while taking up time from teachers who could be teaching tangata whenua? This paper suggests yes, at least in so far as there is competition for places in a class.

and another one about scarcity of teachers, which lies behind the first.