With the preponderance of blogs by regular folks, I would agree with your assessment. I think blogs can be used to enhance profits of another business by talking about a specific topic and providing links to sites that market and sell related products (the essence of SMM). But even there the profits are limited. The only industry that I can see making a profit using blogs would be sports betting. There are many phone numbers you can call to get betting advice and expert picks and I think doing the same with a blog and tying it to an online betting service (or even a telephone betting service) could drive some serious profits.