Answer
No. PowerVS extends the Power servers you already run into IBM Cloud without changing the operating system, the Db2 for i database, or the RPG and COBOL applications running on it. watsonx connects to that environment as a separate AI layer through APIs and data connectors, so the ERP and the business logic underneath it stay exactly where they are.
The realistic path is incremental: extend infrastructure into PowerVS where it makes sense, connect watsonx to a specific, narrow use case, and prove it against real data before expanding scope. A full platform replacement is a much higher-risk move than extending what already works.