Continue to be great at what you do and hope for an opening in management is not a career plan. That is what appears to be on offer at many companies though. They aren’t preparing anyone to be a manager in the future, and they aren’t increasing headcount that might require more team leads and managers, so how long do we expect people to wait? Add in the number of “senior” folks with higher salaries who find themselves part of a reduction in force, or the number of people who’ve watched their current job change over and over until they find themselves doing work they never signed up for in the first place, and it’s no wonder that workers are taking responsibility for their own growth, by choosing workplaces that give them better opportunities.
No one has to stay and work for you for the next 20-25 years. They can, and will, go elsewhere if there’s no clear path forward. I don’t blame them.