Web languages want to be standardized. Once the creators hand over the reins to the World Wide Web Consortium and Ecma International, their language gets a universal stamp of approval and a red carpet to mainstream browser adoption and wide developer use.
Ecma has already established a committee to publish a standard specification for Dart. By the time it’s published, Ecma will have rolled out ECMAScript 6, a major update of its own addressing many of the shortcomings Google initially set out to improve upon with Dart. By 2015, the two languages will be structurally on the same playing field.