He said in the article:

When hiring someone new, companies are forced to play in the open market, competing for top talent. But internally, they create opaque and informationally asymmetric compensation structures designed to minimize growth for existing employees to save the company’s bottom line.

So yes, this is totally just how many (most) companies are run. I work in healthcare and have faced similar issues, where someone I hired as a new grad who accumulated 5 years of experience with me would be making $20K less than someone I just hired who had 5 years of experience somewhere else. I always had some words for anyone who tried to talk to me about retention rates