The browser and developer adoption simply hasn’t materialized. Through the language’s 1.0 release, incremental versions and Ecma standardization, Dart’s developer popularity peaked in late 2014 at No. 17 in TIOBE’s language popularity index. Less than six months later, it has fallen out of the Top 50.
In an early 2014 story on the interplay between Dart and ECMAScript 6 for the future of Web development, ECMAScript project editor Allen Wirfs-Brock talked about Dart’s ambitious path. Google bet on wide Dart adoption from the ground up, rather than taking the superset road of CoffeeScript, TypeScript and even the company’s own Angular framework, now to be written in TypeScript.