You know what they say, "Stuff rolls downhill"
If the applications are supposed to be simple, and if Enterprise Architecture is to help find simple solutions, we still have a problem. The application requirements are driven by processes in the business, and if the business has different groups or markets or products, and each one wants a different process, then we are ill positioned to say "change your requirements for the good of the company."
Without the business having a consistent and simple approach to solving problems in a common way, we may effectively be limited to providing good networking and database management services. The real commonality will be really tough to achieve. SOA can get close, but to do this right, the hydra that is the business needs to speak with one voice.
Some say that IT is the glue, that we can be that voice. I am not convinced. We can sell the idea, but the business has to decide they want simplicity for it to happen. We can advise, but that is all.