"The reason people are quitting today is because the labor market is so competitive that the only way they can get a significant increase in income is by quitting and going to another job."
Well, no, the opposite is true. Employees have to quit because companies stubbornly refuse to be competitive on salary.
The reason for that is mismanagement - managers and HR would be personally criticized for "being soft" if they offered raises, regardless of the benefits to the company of doing so.