Microsoft says – paraphrased – that to make Cortana work as designed she needs to be fully integrated into the search engine, and she simply cannot do that with anyone else other than Bing.
Starting today, to ensure it can deliver the integrated search experience designed for Windows 10, Microsoft Edge will be the only browser that will launch when you search from the Cortana box.
To put paid to the conspiracy theorists, Microsoft benignly adds that of course you can use the search engine of choice in Edge and other third party browsers of choice – its just Cortana’s search that is affected.
As a regular user of Cortana on the desktop, I have noticed that she gives less than perfect results and less functionality when paired to Google search. The same could probably be said of OK Google or Siri if mis-mated too.
Some analysts say that it is Microsoft’s way of gaining more Bing users or to stop that pesky Google search from invading its systems. But Microsoft has been 100% supportive of ‘digital neutrality’ under the leadership of Satya Nadella.
And frankly Statcounter indicates that 90% of searches are via Google – with Bing only having 3% of the market so it could not be a case of exercising market might.
You can read more in Microsofts Blog here.