While almond milk definitely feels like a new (and growing) trend, nut milks - almond in particular - have been around for centuries and were popular across cultures and religions from China to the Middle East to Europe.
In fact, nut milks were a staple of Medieval kitchens largely because refrigeration (and pasteurization) did not exist. Most recipes calling for dairy milk at the time advised cooks to only use dairy milk that came directly from a cow, from a source they trusted. This was often not possible for people living in cities. Purchasing milk from a milk seller was considered a questionable practice because many street sellers often sold milk that was either spoiled or diluted with water.
Rather than buying dairy milk that they couldn’t trust, Medieval cooks turned to nuts - almond and walnut, in particular. Unlike cow’s milk, nut milk could be prepared fresh on-demand and in whatever quantity the city cooks needed. It could also be prepared ahead of time and stored with less danger of degeneration than unpasteurized cow’s milk. Nut milks were even turned into butter!
Think about it - in Medieval times, people were drinking room-temperature almond milk that was most likely chunky in the absence of electric blenders and grinders! Today we are lucky to have better machinery and refrigeration so we can make our milks smoother, colder, and therefore safer. What a long way technology has come to improve upon a simple recipe!