I did think it was weird that Microsoft was making this big, ongoing open source push everywhere but a place that it might restore their relevance in a dramatic way: the browser.
For my own experience, I know of two large organizations who were Microsoft shops that unabashedly avoided Edge in favor of Internet Explorer, and showed no signs of switching ahead of this news. Now I have little doubt they'll hang on to IE as long as possible and then just bump everyone to Chrome. Sure, Microsoft will put out a "Bing Browser" (I'm choosing that name because it's just Chrome with a bing.com home page), but I can't imagine why anyone would use it.