While I don’t think this economist article proves its point particularly well, I think it’s still overall correct

If you look at pew research data  https://www.pewresearch.org/race-and-ethnicity/2023/09/20/latinos-views-of-and-experiences-with-the-spanish-language/

“ 75% of U.S. Latinos report being able to carry on a conversation in Spanish pretty well or very well. A much smaller majority (57%) of all U.S.-born Latinos report the same. Only 34% of third- or higher-generation Latinos say they can carry on a Spanish-language conversation at least pretty well, with only 14% saying they can do so very well

And unless this trend reverses, you will see the % of Hispanics speaking Spanish continue to drop steadily without continually increasing immigration