[NyxWulf]

I agree with Paul's comment. The 250 number feels low to me, but that is applying a specific model. Typically people come with some set of favorite models, and many of them provide that vast majority of the benefit a business needs. Especially when the current model in use is slipshod and busted at best.

[rch]

The 250 number refers to the medical field. So the requisite background includes at least biology, and more preferably clinical experience. That diminishes the pool somewhat.

A similar phenomena certainly manifests in other highly specialized fields though. There are far fewer people with both the skills we're talking about, and deep water E&P or big 3 audit experience, for instance.