Watch the following presentation on Dart language.
Now think about what Google has been doing with its biggest push yet: Google+. Plus has native apps on Android as well as iPhone. However, it also has a pretty good web application. So here is my little hypothesis:
A long term reason why Google wants to be a big player in the native mobile platform race is so it can nudge the industry to a faster adoption of the web-based applications on mobile.
Dart is just another little hit to chip away at the dominance of native and another little push towards the web. It makes developers used to native applications feel "at home" developing solutions on the web. People like familiarity, as Microsoft has long discovered and utilized in PowerPivot and Excel Services in SharePoint 2010 (which draw on the familiarity of Excel). (In Internet language, people like familiarity developers are just people as well.)
Exhibit A: People like familiarity and predictability. Please go ahead, Film School Rejects
This tells us that while American film lovers like to pretend they want new stories, new characters and new reasons to go out to the movies, they are – in reality – in love with what they know.
Exhibit B: Wikipedia, of course! Mere-exposure effect
The mere-exposure effect is a psychological phenomenon by which people tend to develop a preference for things merely because they are familiar with them. [...] In studies of interpersonal attraction, the more often a person is seen by someone, the more pleasing and likeable that person appears to be.
This is why first to market advantage is so important for companies that invent new market segments like Amazon.com and that is also why Microsoft needed to do something radically different in mobile if they are to differentiate themselves from Apple's ventures which have the familiarity advantage. But I digress.