The killer problem with mobile web games is monetisation. The app stores absolutely destroy any web based approach for this, hands down, and until that changes even things like the Chrome store will remain ghost towns.
This is really why there was a giant exodus of game developers from Facebook to mobile platforms in the first place.
And as these types of games can be quite addictive, while using JS made them easy to share over Twitter or Facebook, no wonder they were so successful.
For the moment there is nothing indicating that these two free successes could lead to the commercial success of paid web games. At least nothing so far that would make developers migrate from native apps.