1) Although "Moonrise" is perhaps Adams's best known image, there are many other Adams photographs that are more complex and, I think, more expressive of his personal vision.
2) One of the great lessons of photography is that nothing lasts. You never step in the same river twice. Instead of lamenting this absolute fact, photography celebrates the flow of human life, the ephemeral reality in which we live. It's what Japanese culture has long celebrated at cherry-blossom time.
3) Technological change is important. We, as Heidegger wrote, live within technology, whether we want to or not. But when it comes to art, it's the the artist's sensibility that matters most, the tools are secondary. The real limitation is the limitation of one's talent.