I guess the first tree-related job I had was working for a local logger in the afternoons and evenings splitting firewood... with an 8-lb maul. After a while, I started running a saw for him, and he taught me how to fell, buck, skid, grade, and sell timber. After about a year with him, I went to work for an old Austrian dude that really knew his stuff. He hated everyone, except me... he was a miserable human being in general. I ran a saw for him, a big Husky (I'm a Stihl guy... does a Husky 1080 make sense?), felling timber, for about a year. After he died, there was no one to take over for him, and his gear was siezed as part of his estate and sold off.
I was cutting firewood, which I was harvesting off the back acreage at my dad's farm, when people started stopping and asking if I was selling firewood. I wasn't, just cutting and splitting for personal use. After the 10th or 12th person stopped and asked, I was in the firewood business. As my name got spread around town, people started asking me if I could remove their trees. I was good with a saw on the ground, and I took on several jobs that I could accomplish easily from the ground. After a while, people started calling wanting to know if I climbed. I was in the process of explaining to one woman that I didn't climb, when my dad snatched the phone out of my hand, and yelled "Hell yeah he climbs, he'll be by Friday!" and hung up on the woman.
My dad was in the line construction biz for 42 years, and immediately took to teaching me the ins and outs of a belt and hooks. Granted, in hindsight, he tought me just enough to be dangerous, as linework and arboriculture are two completely different things.
I started getting more work. I also took a job at the local Agway, where the Nursery Manager was a former tree guy, had his own business back in the day. HE took to teaching me the latin names of most of the Northeast Species (alot of which I have since forgot) and showed me how to climb with ropes, and knots and hitches, and alot of other sacred tree knowledge. I was also handing out business cards like crazy to all the rich people who came up from NYC to spend the weekends in the Adairondacks. The business grew quickly from an old Ford Ranger and a Poulan Pro (it hurts to even mention it...) into several trucks and pieces of equipment, and all the Stihl saws, ropes, rigging gear, and everything else to support the biz.
So to answer your question after all of that blabbering, I dont think so. I think it is valuable to know all aspects of the business for several reasons, and one fo the best ways to gain that experience is from starting at the bottom.
Sorry for the disertation,
T