ROI from Enterprise Architecture

It is difficult task to measure the ROI on Enterprise Architecture. Few activities of Enterprise Architecture includes -
1) Defining standards and guidelines.
2) Preparing reference architecture
3) Defining and maintaining IT roadmap
4) Governance activities.
5) Consultancy
6) Defining Strategy for moving from "as-is" to "to-be" architecture

Point number 1 and 2 produces various kinds of artifacts about Application, Information, SOA, Security, Content Management, B2B architectures. Various teams refers to these document and extend project architecture from these artifacts.
ROI - Is it possible to find out how reference architecture benefits the project architecture. How it saves time, add value, improve quality of project?

Point number 3 produces the IT roadmap for different elements across the layers. Any project should refer to this roadmap before finalizing the technology stack and aligns with it.
ROI - Is it possible to find out the operational and maintenance cost saved by aligning with predefined roadmap? Is it possible to find the effort saved by project when it adopt the preferred technology from roadmap instead of evaluating different products, technology and protocols.

Point number 4 includes activities like reviewing and approving architecture for projects. Assuring that projects are following standards and guidelines.
ROI - Is it possible to find the value of improved quality in project due to assurance from EA?

Point number 5 includes EA mentoring, coaching and guiding Solution Architects to align with standards, directions to follow best practices, refinement of the solution architecture of projects.
ROI - Is it possible to find the whether directions were right or wrong, whether they are adopted or not?

Point number 6 requires vision and leadership qualities. EA defines the long term strategy inline with Business Architecture. This helps in reducing the cost of IT in long term. It increases the agility of business. It simplify and standardize the architecture and implicitly increasing the stability, flexibility and extensibility of IT.

Above points shows lot of activities, but is it possible to measure the extent of benefits from these points. These benefits increase with time, they are like snowball which gathers momentum and becomes bigger as it falls. All these points prevents problems to occur in future.

May be it is easy to measure the benefits at enterprise level instead of project level. Identifying major architecture issues in enterprise like re engineering of legacy application, producing enterprise level reusable components, product engineering, improving integration of various application or deciding Build vs Buy. All these benefits of EA provides the ROI and help in building the metrices for EA ROI.