South Louisiana native here with a few Cajun and Creole friends:

French language and culture eradication was official government policy into the 1980s. Teachers were instructed to punish students who spoke French in class (the canonical punishment was kneeling on uncooked rice). Only with the rise of cultural tourism did this policy end and did revitalization attempts begin. They've had limited success, have been racist in their implementation, and have largely just resulted in more Metro French education, rather than either main branch of Louisiana French. As a result, I think rates of French speaking are continuing to decline, and the unique dialects themselves are definitely declining.

For a bit of background here, Louisiana is generally considered by most residents to have two "distinct" groups of historical French-speakers: the Cajuns and the Creoles. Conventional wisdom has been that the Cajuns were descended from the Acadians expelled from the Canadian Maritimes, whereas the Creoles are descended from French colonists and imported African French colonial slave labor, along with some admixture from Native Americans. Cajun and Creole cultures are considered distinct, with Cajuns generally living in the southwest of the state, centered around Lafayette, and Creloes living in the southeast. More bluntly put, to most Louisianians, if your grandparents spoke French and you are black, you're Creole, and if you are white, you're Cajun. There's been a lot of scholarship around this lately to try to unify these identities, arguing that this bifurcation is pretty ahistorical, but that's still not widely accepted. (The more fun way to say whether someone is Creole or Cajun is if they put tomato in their gumbo.)

If I had to guess, I'd say the fact that the French-speaking bloc was generally always poor, but then also split along racial lines greatly diminished any capacity it would have had to advocate for itself throughout the 20th century. Racial politics more likely trumped ethnolinguistic unity.

Anyway, the end result is that vanishingly few young people are native Louisiana French speakers. Anecdotally, I had a friend from Cut-Off (real place name) who could understand a little when spoken to him, his dad had full comprehension, and his grandparents were first-language French speakers.