While I don't doubt that powerpoints about quick easy money from advertising were legion in Redmond, it doesn't change my belief that Bing has been a significant success for Microsoft despite the money being neither quick nor easy. The notion of measuring the success of the Bing team against the whole of Google is silly. Bing's success should be measured solely by the business benefits it provides to Microsoft.

I find this statement confusing. Perhaps in terms of absolute numbers, infrastructure costs are less at smaller scale, but as a percentage of revenue, larger scale usually shows increased infrastructure leverage, until you get to Microsoft/Google/Facebook size, and start designing your own Servers, Power Supplies, Storage, etc...

It's completely reasonable to compare companies against each other to determine their success - particularly when being the leader gives you network-effect benefits.

It is also important to acknowledge the opportunity costs for Microsoft that scaling Bing might entail, e.g. is infrastructure more profitably used for cloud services or search? Does an advertising revenue model interfere with the necessary trust which underpins Microsoft's business relationships with enterprise customers?

I am not saying it is unreasonable to compare Microsoft with Google at the corporate level - but using Bing and Google Search as the primary criterion for such a comparison is a category mistake.