I check again this morning, my residential/casino city is still not showing any visitors. And my commercial and industrial cities are not doing well, still requiring more workers which should be provided from the first city. This is starting to get annoying.
Edit: Duplicate, deleted.
Worker Sims do not posses education nor tech level properties.
Students carry "education" to the buildings they return to.
Universities and Community colleges provide resources for industries to increase tech level the same way as a water tower provides water. Water towers draw water from the water table, and send out water agents to buildings. College and Uni draw resources from the attending students, and pump "tech level agents" to the road network, sending them to the industrial buildings. These agents doesn't leave the city border.
