Recognize that your Level 4 architecture function is a large IT portfolio

As you advance your architecture function toward Level 4, resist framing horizontal ownership as something architecture does in addition to its governance and advisory work. When your architecture function owns a portfolio of horizontal platforms that every vertical IT portfolio depends on, it is — by any fair organizational measure — a large IT portfolio. It has a budget that reflects the cost of designing, building, and operating multiple enterprise platforms. It has a roadmap reflecting the planned evolution of those platforms over a multi-year horizon. It has stakeholders: the vertical portfolio leaders, business function heads, and executive sponsors whose operations depend on its platforms.

This framing matters for how you position the function organizationally and how you defend its investment. A governance overhead function is evaluated on advisory output metrics. A large IT portfolio is evaluated on operational performance, delivery track record, cost per consumer, stakeholder satisfaction, and roadmap execution. The second evaluation is harder to pass but far more durable in its organizational consequences — and it is the right evaluation for the function you are building.