I've been in management for many years and have been involved in layoffs. I can honestly say that my company has never, ever, laid off a good worker. Whenever we have to do RIF's (reduction in force), we use it as an opportunity to rid ourselves of deadwood and other "high-maintenance" employees.
Now maybe there are companies out there that layoff their best people. But I've never worked in such a company.
I know of at least one such company. By and large it appears to work as you say, but not always. Of course you can see it as a company that statistically is grossly underpriced compared to its peers. It takes looking into its stupid management style to see why its stock prices are so weak.