The problem is a culture that doesn't care about history in general. I'm a high school teacher, and though I am a professional artist, I am teaching English too (I have an MA in history and literature in addition to my BFA in photography). My students did not know what Communism was when I mentioned it in regard to a piece of literature we were discussing! The Soviet Union fell before any of them were born, but still....Communism is not ancient history; it is still pretty recent, and a few countries still call themselves Communist (Though I'd argue that China is now Capitalist).
If teens today do not know what the USSR was or what Communism was...recent history....then how can you expect young photographers to know about Stieglitz or Weston, who were early pioneers in fine art photography.
Another thing is that the world has simply changed to radically for Weston and Steiglitz and their concerns to have any relevance to young artists. I see my English students taking photos all day long with their phones; its instant imagery, immediate and relevant in a world with no attention span. Yesterday, a Mexican kid in one of my classes called a black kid a N----r and made a racist joke about him. The black guy ignored him at first, but the other guy just kept saying stuff. Finally, the black kid says to the Mexican one "Hey I may be a N----r, but at least I'm not a dumbass with two kids when I'm in high school!" Whoa! Two kids? Yep, the guy that started the fight already had TWO kids. He's a junior in high school. Finally, it became a fistfight that I had to break up. EVERY kid in that class crowded around us snapping away with their phones, and they probably had their photos of the fight on Facebook before the guys reached the principal's office! That's the world these kids live in.