Yeah, a lot of layoffs make a lot more sense when you re-evaluate the assumption that these CEOs are hiring people with the intent of keeping them indefinitely. For many, I'd bet this was the plan all along
Another important point is its not the case that all the hiring is LIFO. In fact we know that many old-time googlers were let go. I am sure many of the more recent hires have stuck around.
Whether that’s a “good” property of the system or not, I suppose depends at some level on how you feel about capitalism. Should a business owner be allowed to fire an employee to maximize their company’s value, and eventually their own income?