This is more discussion on the real world trys at SOA. Those that come from the EAI world know how this works. Many of the EAI projects failed for a lot of the same reasons.
I do think it is important to define what the "business" is. IT is itself a business and SOA has value there. Yes even in a corporate IT shop. There are numerous "business systems" within a corporate IT shop that can benefit from this type of architecture. A lot of these systems are not customer business systems but yet still have an impact on the overall cost and agility of the overall business.
It is an underestimation of the value of SOA to not include the "business of IT".