There is a difference between stock photography that sells and being what I will call an art photographer who produces a product. Stock is a service, ok you can produce it on commission, but essentially your best bet is generic images - children playing in a classroom, an office worker, a perfect green hill with a white picket fence.
Art photography, if you'll pardon the expression, to my mind supplies a client with a vision from your mind which satisfies them to the point where they want your style, not a particular image - the exact opposite really - you're showing a uniqueness which people want to purchase.
I don't doubt that you can make a few quid here and there with stock and that if you devoted yourself 9-5 to producing stock images then you could make a living of sorts for a while. However you have no relationship with your customer and no control over your work's application. I prefer to do a couple of model shoots every now and then and the odd wedding or party and get a few thousand.
My point about the online stock market was not that all people who use it are idiots, it was more that people can and do submit second-rate images virtually rights-free. This cheapens the lower end of the market to the point where people stop worrying about quality and start thinking how cheaply they can buy their images. It also makes it much more tough for anyone who wishes to be a full-time professional to make money.
You are obviously interested in producing product or service advertising photography - you're probably not going to be able to make a living out of this, precisely because of people like yourself selling images for pennies. It affects the industry as a whole, by spreading the money wider and through more hands.
Rob