I guess it depends on the school you go to. I'm not implying any causation, but schools below the top 50 generally place phds in the private sector more than academics. This is not only based on how competitive the market is, but also students' interests. These schools are typically composed of more foreign students. Whether this means foreign students go to the school for private sector jobs, i don't know? It might mean that there are only private sector jobs available, i don't really know.
I would say that it would be extremely extremely hard to get a phd from a place ranked below 50 and then get a job at a higher ranked institution. Typically new graduates get a job at a school significantly lower until they prove themselves through research. However, it all depends on the individual.