Are you sure you want to be mainstream? (Loud Thinking)

David Heinemeier Hansson cautions against Rails becoming "mainstream" in Are you sure you want to be mainstream?

One of the major boat anchors around J2EE's neck is the requirements for backwards compatibility. Did you know that for a J2EE application server to support forward specifications like EJB3 and remain certified, they need to also support all previous EJB standards? This is the price you pay for being "mainstream."