Well, first, I don't have a high opinion of Neo4j. Secondly, SparQL queries are pretty distinct, and while, yes, they can be translated into generic graph queries, I'm pretty sure there are some fun optimizations to be had if you focus on their patterns 100%. Thirdly, because it'd be a hell of a lot of fun! Why else would anyone write a database...
> Thirdly, because it'd be a hell of a lot of fun! Why else would anyone write a database...
Presumably, because you have a business, which has a product, which has a nascent feature, which requires some particular set of time-and-space-and-distribution guarantees that no current database on the market makes. This is why, for example, Cassandra was developed.
