Some time ago, when I was first having fun with a drop spindle and spinning my own yarn, there was a curious woman. She asked me what I was doing, and then asked me if I knew I could buy yarn at a store.
I'm sure she thought she was funny.
But there are people out there that will ask us why we would make something that we can go to the store to buy. Society also seems to degrade the work that goes into craft work - it's a hobby, it's something to do in addition to "real" jobs or "real" work.
When I buy roving or fleece, I am generally buying from the shepherd/farmer. There are a few exceptions, but I'm never more than two people removed from the sheep. Often, I can tell you the name of the sheep from which the fleece came. I'm supporting local business, and supporting "hobby" farmers.
I spin the roving I get. Sometimes, I have to wash and/or comb/card the fleece I get first. I have to spend my money to get the supplies, and then spend my time to make the yarn. But everything there is made by one person (and often I can tell you about the breed, the best uses for that type of wool, and if it will felt/full).
When you go to the store, you're buying quantity. You're buying a standardized product. Often, you're buying mostly acrylic (plastic) and some wool. You don't know what type of wool you're buying, or where the animals are located.
Have I ever bought yarn from a store? Yup. I have. And I still do on occasion. But more and more often, I buy from people like myself who spin it. And when I give a gift, and some one says "Oh, that's nice, a scarf/pair of socks/vest," I do tell them how much time went into making it. Not to make them feel bad, but to make them realize how much I love them. Okay, to make them also realize just how expensive a handmade item is.
Will I get rich spinning wool? Probably not. I hope to make enough to cover the cost of my next fleece purchase, taxes, and maybe a little extra. Enough to keep going and support some of the other "hobbyists" trying to make a living.