I'd love to see some research about this from an unbiased source showing that targeted advertising produces great results in small businesses (<100 employees, or <5M revenue yearly).
My personal experience is that it is pretty hard to get consistently good performance running campaigns on FB or Google. It requires a lot of learning and a lot of trial and error. On top of that, they constantly push you to spend more by giving you dubious recommendations on how to “improve” your campaigns. Very hard to believe that the average small business is actually capable of running good campaigns and consistently make money from them.
Keep in mind I'm talking about targeted advertising, not advertising in general.