It pays off for Google to develop Chrome, because:
* they can feed Chrome Sync data into their advertising databases.
* it means that they don't have to pay other browser vendors quite so much to make them the default search engine.
* they can take control over webstandards for their other profit-driven purpose.
* they can hinder the blocking of their ads.
Mozilla can't or chooses not to rely on any of these profit schemes, so they need other ways of making money.
