The $50 Kitkat Android phone
gizbot.com
gizbot.com
Furthermore, Web pages and Web apps can easily out-consume the fattest resource-heavy apps, and a Web runtime is no lightweight compared to ART (or Dalvik, for that matter).
It just doesn't make sense to target a Web OS under the kind of hardware Android will run on.
(This smartphone at this price-point is actually an extremely big deal for the gigantic emerging African market.)