Sorry. Some Marketers are Imposters
Marketing is a difficult discipline, but some articles on the subject comically miss the mark. The author of this article is surprised by the large proportion of Marketers that suffer from imposter syndrome. That is, they don't feel they are good at their jobs. His cure is to ask marketers to realize their worth by comparing themselves to other marketers, most of whom aren't good at their jobs.
Stating the obvious, if most marketers are bad at their jobs, the real question is why do only 30%-40% of them suffer from imposter syndrome?
The impact of some marketing is easy to measure. The impact of other forms (like branding) is harder to measure. And even where you can measure it, it's even harder to demonstrate the cause-and-effect relationship between brand strength and marketing efforts. This is why Marketers have to work hard to justify their work.
But rather than do this hard work, many (probably most according to the author) marketers rely on soft metrics (like likes, rather than sales) or customer acquisition targets (rather than the estimated future value of consumer expenditures).
Soft targets make life easier for a marketer, but second-class targets relegate the discipline to second-class status.