The reason I say this though, is because if they knew how to run ads properly they would have been tracking their results from the start, and would have known much earlier whether they were getting a return on their investment.
If your only way of measuring advertising results is to "turn it off", you're just flying blind, and one can't expect success with a (lack of) strategy like that.
That said, you are not wrong that a meaningful percentage of advertising is being run with similarly insufficient statistical power, and to that I would say those businesses are also incorrect, for the most part. I delineate because at some point, say when you're Apple or Microsoft, you are so big that "brand awareness" advertising takes over performance advertising. For the most part though, I'd say those aren't the types of businesses we are discussing in a context like this one.