Or, at least, why it's an afterthought:

We're about making better products and what I love about the consumer market that I always hated about the Enterprise market, is that we come up with a product, we try to tell everybody about it and every person votes for themselves.  They go "Yes" or "No" and if enough of them say "Yes", we get to come in to work tomorrow.  Ya know?  That's how it works, it's really simple.  As, where the enterprise market it's not so simple.  The people that use the products don't decide for themselves.  And the people that make those decisions sometimes are confused."
- Steve Jobs, D8 Conference, 2010

The idea that some idiot manager/IT person gets to decide what a user gets to use for their day to day use must drive Jobs crazy.  As it no doubt does for a lot of people working under an idiot manager/IT person who can't see past their own ego and dogma to use what's actually best for their staff/clients.