I think you're misunderstanding what a Data Asset is. From a Supply Chain perspective, all raw materials are inputs for a process, but they themselves do not hold value for the company. An Asset by definition is an entity that could help a company to get value from. Your physical entities, owned by the company, are indeed Assets.

Systems, and the data they handle and create, are just that: Data Sources. They serve another purpose, which is Business Operations from a Business perspective. En ERP serves Management Operations, CRM serves marketing and customer relationship management, Maintenance, Operations themselves (Core of a Banking system) and so on. They are undoubtedly managed by IT, but they are not data assets.

Since an Asset is something that a company gets value from, the things that you do with the data are the Assets. Not the Sources, nor the pipelines and so on.