The OSGi Alliance recently held a workshop on applying OSGi to the enterprise. You might find it surprising that a technology initially created for small devices is starting to be used on large enterprise systems such as application servers.
But businesses need to keep their IT costs down, especially price/performance. Salaries for application developers, operations staff, etc. can be reduced by using languages such as Java and standardised middleware. But if that impacts performance, then price/performance suffers.
OSGi provides good support for Java modularity, versioning, and lifecycle management but is also efficient because of its roots in small devices. Modularity helps keep development and maintenance costs down; versioning and lifecycle management reduce operational costs.
So, apart from the coolness of OSGi technology, I would expect its price/performance to appeal to middleware vendors and their enterprise customers. I would also expect customers to see value in using OSGi directly, e.g. in conjunction with Spring.