The textbook for this course is a great resource for running your own general contractor business, but a lot of AEC activity happens in large, nationwide or multi-national firms.  I've been involved with both, from my own general contractor business early in my career, to my time at Albertson's.  The biggest differences between the two are really just the number of zeros before the decimal point and how many people take care of back office functions.  The big firms have whole departments of people to take care of HR, Accounting, or IT, while the smaller firms often have the same person doing all three of those and more!