Why selling SOA projects is harder than selling EAI projects?

My team started to perform EAI projects some time ago. We have experienced what happens with new technologies. Initial sales were hard, but they became easier with time. Now we start to sell SOA projects and we are realizing that this is even more complex. The main reason is SOA adoption requires a broader change in IT environment.

EAI emerged to organize exchange of information between applications. Applications always had to exchange data. But, prior to EAI there was not a standard way to do that. The connections between applications were point-to-point. When an application was changed, all the applications connected to it had to be changed too.

EAI introduced a big change in this scenario. All the applications were directly connected to the EAI middleware through standard adapters. But, it is important to notice that this was not a big change in each application itself. The structure and concept of the application remained the same.

On the other hand, SOA requires a deep change. The concept of application is different. It is necessary to break down the systems into services. Then, the applications are created with these services. This architecture makes it easy to reuse assets and aligns IT with business needs. It is clear that this architectural change is bigger than the change due to EAI adoption.

In my opinion, selling SOA projects is hard due to more than the newness of the technology. The actual reason is the wideness of the change.