I think that this is probably the most insightful comment on this page. Microsoft can probably afford for Bing to fail, because it's not their bottom line. Their bottom line is licensing with OEMs and large businesses.
I love Google products, but from a business perspective, their only source of profit is search advertising from their search engine. They are basically bleeding money through Youtube every single day with apparently no clear way to generate revenue.
If Microsoft can focus on the domain of searches to very profitable topics, such as airline tickets and hotels, and provide a better user experience through statistical analysis and information, they can carve out a part of the search revenue. No one is going to seriously use Bing for casual search, Google is too good and too entrenched for that. But, perhaps for some areas, they might turn to Bing.