I will here recap some of the points discussed, since these can be of broader interest.
Why is there no single dominant vendor?The field is young. We can take the relational database industry as a historical precedent. From the inception of the relational database around 1970, it took 15 years for the relational model to become mainstream. “Mainstream” here does not mean dominant in installed base, but does mean something that one tends to include as a component in new systems. The figure of 15 years might repeat withRDF, from around 1990 for the first beginnings to 2015 for routine inclusion in new systems, where applicable.
This does not necessarily mean that the RDF graphdata model (or more properly,EAV+CR;Entity-Attribute-Value + Classes and Relationships) will take the place of theRDBMS as the preferred data backbone. This could mean that RDF model serialization formats will be supported as data exchange mechanisms, and that systems will integrate data extracted by semantic technology from unstructured sources. Some degree of EAV storage is likely to be common, but on-line transactional data is guaranteed to stay pure relational, as EAV is suboptimal for OLTP. Analytics will see EAV alongside relational especially in applications where in-house data is being combined with large numbers of outside structured sources or with other open sources such asinformation extracted from the web.
Can there be a positive reinforcement cycle (e.g., building cars creates a need for road construction, and better roads drive demand for more cars)? Or is this an up-front infrastructure investment that governments make for some future payoff or because of science-funding policies?