So much depends on population dynamics and resources. Life gets better and better until there are too many people and wars break out. Then trade disappears along with most of the people, and the cycle starts over again.
Late Woodland (or middle -- I forget how they classified it) in much of the north east here begins with the charcoal layer. Where there had been an amazing number and variety of cultures, each carefully exploiting a defined lithic resource (and probably susbistance strategy), after a certain point, they just disappear. The village sites are burnt and the artifacts mostly pot-lidded and fractured from heat. After that, the triangles begin.
This corresponds exactly to the oral history of the tribes in Pennsylvania and New York, who recount that their ancestors had fought their way in, finally managing (at horrendous cost) to overcome and annihilate the Alleghwi giants.
Old (like nineteen fifty something) archaeological journals I used to have had articles about hilltop fortifications from the tail end of the Hopewell era. Dragoo (back when people could still talk about this stuff), said that the Adena people (this is from memory, so don't hang me) had been driven out ; many of them going down the Mississippi and founding the Copena culture, with others heading north up the other side of the Alleghenies as far as into Maine. Even the Trail of Tears displacement sent just enough refugees north to escape it, following the mountains, that the extremely used-up artifacts of southern cherts that mark their trail can be (rarely, but often enough) found up the Susquehanna valley and into New York.
Point is, that the extensive trade eras correspond (from what I can determine) with the economic fat times. The Archaic-into-Woodland sites I hunted in Montour Co. (Penna.) produced an amazing variety of traded-in materials from 100 and more miles away. Berks Co. Jasper from the east, Houserville Jasper from the southwest, Rhuolite from the south, Quartzite from the southeast, Argellite from wherever it comes from, Onondaga from New York, &c. That whole show stops in the charcoal layer. After that, triangles.
History anywhere is ups and downs like that. For a real good handle on one corner of this, showing the way it played out in near-historical times, check out
http://www.siftings.com/late.html