There not too many Vietnam Veterans left if you haven't noticed. Not many of us will live to be 100 years old. Most of my Brothers have died between 64 & 74. I am crowding 70 myself and seriously doubt that I'll be drinking a beer at 104. Old Soldiers do die and are quickly forgotten until the next generation has their turn.

We had one pop up a few months ago, but they are (understandably) pretty rare.
Not a lot of nonegenerians in the meme-posting business.
They worry about more important things, like drinking Coors Light as a magical elixir.

I went to a birthday party for twins who had served and turned 90