Enshitification is often a company-wide culture problem, but the fish does rot from the head.
There are a variety of reasons why a company might begin to over-incentivize short-term gain (or high-stakes risk-taking) at the expense of customer happiness and possibly to the detriment of the company's long-term interests.
For example: Growth stagnation, an existential threat, a pessimistic long-term financial outlook, bad reward structure, low customer regard, organizational infighting, low employee retention, etc.
The sudden emergence of AI and volatile economy are triggering several of those for a boat load of companies. And, well, show me the incentive and I'll show you the outcome.