Are there any unexpected benefits to having hundreds of
breeds?  I didn’t used to think so, but
now I’m not so sure.  My great concern
for many pure bred dogs has been the terribly small gene pools that many fine
breeds have relied on over the decades. 
When you see the medical messes that some dogs have become, and realize
that it is often caused by the pairing of undesirable recessive traits due to
the inbreeding of closely related dogs, you begin to wish for those gene pools
to grow, or at least be less regional. 
It’s why mixed breed dogs usually live longer, healthier lives (albeit
with less ability for us to predict temperament and size).