Based on available data, milk consumption appears to be declining over the next several generations in several countries.
In the United States, per capita consumption of fluid milk has been in decline for more than 70 years and has declined at a faster rate during the 2010s than in each of the previous six decades.
From 2003 to 2018, consumers of all ages in the United States consumed less milk as a beverage than the primary form in which milk is consumed, fluid. Plant-based milk alternatives account for only a small part of this decline.
A study by the International Milk Genomics Consortium also found that, worldwide, younger adults drink less milk than older adults.
This trend suggests that older adults are either responding to advice on how to combat osteoporosis or that there is a change in habits between generations.
Finally, one article mentions that, since 1970, per capita milk consumption has declined from 0.96 cup equivalents per day to about 0.61 cup equivalents per day.
In 2007-08, preteen children drank, on average, 30% less milk than children in 1977-78, while Americans over the age of 13 drank 25% less milk.
In summary, the available data suggest that milk consumption is declining among the next generations in several countries.