[abathur]

It should be evident that, with effort, the date of all firsts (and lasts) will continue to approach (but probably never reach) the date of The Oldest (or Newest) Artifact We Can Plausibly Find.

It doesn't take genius, intellectual courage, or prescience to expect this to continue.

There's certainly room for theorizing about what we may find and where, but archaeologists should in some fundamental way be more limited by proof than their imaginations.

Aside: I'd love to see the citation for "They called him crazy for thinking that the Egyptians had structures 12,000 years ago", as I'm a bit flummoxed by who's stupid enough to get any further out over their skis than "we don't have any evidence for that."