I know that I cannot wait until I get to the place where I can afford to have someone else do this bit of the work for me. Even still, even the most successful of bands typically don't have simple muscle as part of their traveling crew. Instead, these bands have contract riders which specify a number of people at each venue to help (item #10, paragraph 2) with loading and unloading. The roadies that travel with the band usually have multiple duties (security, gopher, support system) and extra skills (electrician, instrument tech, amateur psychologist). And speaking of extra skills....
Techs are the unsung heroes of a show. They are the people who ensure that the band's setup and instruments are right. It can be a pretty thankless job, as some musicians tend to be a little bit picky when it comes to their setup and the horror stories of abuse rained down on techs from various musicians are legendary (Buddy Rich quickly comes to mind). If you ever go to a show and you see someone dressed in black run up to a musician and hand him a new guitar, or switch snare drums for her, then you've just seen a tech in action. It's part of the tech's job to make sure that all the instruments on stage work correctly throughout the entire show.
Most bands don't get to the level where they have the luxury of techs; rather, the band acts as their own techs. And, most techs typically pull double duty as roadies for the gear on which they work. If you are lucky enough to have a tech, try to keep in mind that they are probably as passionate about the music and the instrument as you are and treat them accordingly. And, sometimes the techs play on stage when a member of the band gets hurt (see #23).
When a band is just starting out, the hardest part of the business is getting anyone to listen to them. And even harder still is getting anyone to pay for the privilege of listening to an unknown band. The primary job of an agent is to get bands work. Once the work is available, the secondary job of the agent is to get the best deal possible for the band at the specific gig. During the earlier part of a band's career, this is a hard slog, with lots of frustrating phone calls and unreturned messages. When a band is very successful, an agent may get overwhelmed with people wanting the band to come to their venue and perform. In the middle, the agent will typically have both ends — lots of lower tier venues requesting the band and frustration of not being able to get into the top tier venues.