It can certainly be argued that we should be working away from monoculture, but I don't see it happening in the forseeable future. One can use alternative pollinators to supplement honeybees, or to work small plots. But several hundred acres of apples, watermelon, cucumbers, or many other crops just can't be done by alternative pollinators. Also don't forget that many of our primary food species are also exotics. This is cotton country.
Bumblebees are almost as hard to find today as honeybees.
Any bee whose life cycle intersects with cotton bloom is in danger of eradication, unless pesticide laws are better enforced. Dan, if you are teaching permculture to someone setting up a couple acre system, you might assume wild pollination. If you are working with larger plots and not including pollination management, you are doing a disservice to your clients. We had to go back to the basics and start from scratch.