The article doesn’t really differentiate what alt-milks are being grown at scale or factor in locations where this is possible. Certainly oats, soy, and coconut are grown at scale (palm plantations are their own environmental disaster). Nut-milk from almonds or nutsedge aren’t really mentioned. The “insanely less resource intensive” is basically because plants don’t output constantly like cows, so they are absolutely less resource intensive simply because they only produce once a season all at once.