Worst of all, for most businesses there is no benefit in sharing their data. And if there is, only consumers of data care about standardized schemas and methods

Worst of all, for most businesses there is no benefit in sharing their data. And if there is, only consumers of data care about standardized schemas and methods of access. For producers, standardization means customers can more easily switch to competitors. Also, deviation from standards should be expected because producers of data want to have unique selling points. The schema.org stuff is useful, it lets companies use their web site as a decentralized phone book by adding metadata for Google (Maps), e.g. phone numbers, addresses and the like. It's the Semantic Web of opening hours. From a product standpoint, schemas are small technical details with relatively low influence on the outcome: it just needs to work. Unless you're operating at extreme scale, you should put much more work into whatever you actually do with the data. Semantic Web people talk about the Semantic Web because it's what they do. They don't just build X, they create an ontology to build X, which somehow makes X better. And, most likely, slower.