Great article written by James Davis from PA Consulting on the topic PMOs to be or not to be. I liked his conclusions.
The need of PMO (Project Management Office) depends on the size and complexity of the portfolio. But my opion is the same as the writers. There will always be a need for central force to execute the strategic control, keep track of the money and resources, manage dependencies, support the new way of working, manage needs and ideas etc.
The key lesson is to be clear about what capabilities you need in order to deliver your programme or portfolio successfully, but worry less about what you call them.
Love to hear your take on this topic.