"The language can only truly survive if native speakers hold on to it."

That seems to be the single-approach-theory in Canada, as it relates to French (outside of Quebec and New Brunswick, that is). In that case, concerns with cultural loss are inter-twined with concerns with loss of language. IMO, investing all energies on one theory-approach seems odd, especially when opportunities exist to look at multi-approaches to reduce a total loss through investments in new speakers. But, that seems to miss the purists who cling to the cultural past, whi tend to under value the potential of new approaches.