I'm sure there's much more to it, but my initial reaction was to think it was oracle snubbing salesforce in their acquisition of heroku. In the enterprise (which sf targets) oracle is revered, and a robust oracle IDE does help give credibility to ruby/rails. Aptana and ruby mine are the only other ruby/rails IDE's that your run of the mill IT manager would consider full-featured im aware of, and neither of them are backed by a brand as respected in the enterprise as oracle.