From my experience, one of the causes of this issue is that in some companies, the people who are in charge of the money (upper/top management) are rarely also people with software engineering backgrounds. These people are often unable or unwilling to fully grasp the concept of "ramping up a new employee" in the context of software development. The fact that any large codebase will take a smart person 3-6 months to acclimate to and become productive. The fact that other people on the programming team have to help these new people (and therefore lose productivity themselves). The fact that the new person is going to produce more errors and the number of defects in the product will temporarily increase.

If you look into the history of a company (e.g. by looking at how many users in the issue tracker are no longer in the company etc.), it's usually quite obvious when there's a systemic problem - the employee turnover is high. The management is interested in saving money by looking at the market and trying to hire at or just below the average compensation levels. In their eyes, it's cheaper to bring a new employee to the team (and there's always some fresh meat on the shelves of the job market) than to pay the current (experienced) employee more. And in the short term, they're probably right. But in the medium to long term, this approach tends to have a cumulative effect resulting in high employee churn rate.

The problem? Software development is not fast food industry. You can't have high employee churn rates without it manifesting somewhere. But pointing out exactly where and how is not easy (linking causation and effect in a discipline involving multiple people across multiple years is not trivial), especially when you need to link it to the bottom line (the market state and marketing efficiency will mess with your analysis... not that you typically even have access to the financials as a run-of-the-mill employee) and even if you do, there is no reason to expect that you would be able to effectively bring these findings to the management (such work would probably be seen as you overstepping the bounds) or that the management would change the processes responsible (that would be expensive). It's an uphill battle. When you are in a company with high employee turnover, there's typically not much you can do other than to start looking elsewhere. These types of companies will have problems (lower level of respect/loyalty, higher level of product defects, lower productivity, higher technical debt), it's best to leave them as soon as the opportunity presents itself.