Well, I disagree with most of this 3+ year old article. Sure, the SW has got off to a slow start - partially I think because people would look at an XML serialization of RDF data and say WTF :-)

There are good open source tools (Sesame, Jena, Swi-Prolog semweb libraries, etc.) and commercial support (AllegroGraph, etc.) If the motivation is there, the tools are available.

Also, Reuters' Open Calais (free) web services do a very good job at generating semantic data automatically.

The next thing we need is simply more people writing applications that use linked data sources.

A tired cliche, but: this is like FAX machines, eventually there will be more available linked data so the rate of app development will increase, and vice-versa.