From The Verge:
The software giant revealed today that “we will begin testing a change where links clicked on within the Windows Mail app will open in Microsoft Edge.” The change means if you have Chrome or Firefox set as your default browser in Windows 10, Microsoft will simply ignore that and force you into Edge when you click a link within the Mail app.
I can’t see any way that this will end well for Microsoft. User trust, and subsequently active use – the more important of the two for the bottom line, is built around providing a superior product or service and therefore a better alternative to the status quo. History has never been kind to removing user choice.
Disclaimer: I use Edge as my default browser. At first, it was an acquired taste, but it has really matured and grown on me.