When there are hiring freezes and layoffs, it's easy to find good cheap engineers and you hire. When job markets are hot, you put a pause on hiring.
The same goes for many other things. A recession is an ideal time for deep R&D. There's little competition, and it's possible to do long-term thinking. When the recession ends, and the bubble begins, you hit jackpot.
All of this requires deep enough pockets to weather a few years, though, and patient investors. That's rare.
Cargo culting for Google and Facebook make little sense organization-wide, since they do have deep pockets. They make complete sense employee-wise. No one got fired for following industry best practices, conventions, or cycles.