I agree, in principle that the most dominant, important technology will be graph databases. The reason I think so is because of experience working in technologies related to the semantic web.
However, there are reasons one might a Distributed Document Store to implement a graph store - it's the index that matters. MySQL is not the same thing as InnoDB/Sphynx. Graphdb product X could be built on mapreduce +CouchDB+Lucene(+somegraphindex) .
The only thing I'm sure of, is that if anything stands out above the rest, Oracle and IBM (and maybe MS) will try to buy it.
However, there are reasons one might a Distributed Document Store to implement a graph store - it's the index that matters. MySQL is not the same thing as InnoDB/Sphynx. Graphdb product X could be built on mapreduce +CouchDB+Lucene(+somegraphindex) .
The only thing I'm sure of, is that if anything stands out above the rest, Oracle and IBM (and maybe MS) will try to buy it.