This definitely would sound like a very plausible theory, except most times it's for companies which have only one (or maybe two) products. To me, it seems more likely that they are getting swindled by some ad company helping manage their campaigns, but that could be my bias against many of those types of companies showing.
While that could be a factor, it usually amounts to a combination of poor targeting, and other harder to control factors like loss of cookie data and cross-device tracking challenges that can easily create these situations.
It is much messier to manage in real life than people think.
