Well in other consulting worlds, and lucrative ones at that, they specifically ask for people like C++ experts, Java experts, Fortran and Cobol experts etc. Heck, I've seen people specialized in some specific vendor toolset get top dollar from consulting.

Just like our field.

You just need a mix of real experts, the ones dealing directly with the customer on site, with a blend of not so experts hacking along a few lines behind in the battlefield.

When one those "not so well experts" gets the next gig, they are themselves experts in the said technology. :)