Perhaps there were a number of environmental constraints for such a large enterprise such as the depletion of fuelwood necessary for the roasting pits used to process the agave. The extent of the Hohokam was quite broad coincident for the most part with the extent of the Sonoran Desert. These people were the shell traders of the southwest. Trade routes to the Gulf of California have been documented. The shell brought to the area from the gulf was transformed from raw shell to beautiful jewelry and decorative items traded as far away as Utah and Colorado.
Trade implies exchange of ideas and information with trade partners.
The desert dwellers knew of oceans and mountains but continued to live in this harsh but beautiful place. The Spanish explorers brought a variety of plants and animals to the Sonoran Desert. They brought horses, cattle, fruit trees and domestic crops that are still with us. They brought diseases that killed native peoples. They also brought religion that changed the ideology of many of the native inhabitants and left us with beautiful missions.