Well its clear that Microsoft as a company has abandoned the browser wars and the clear winner is Google Chrome, with Firefox as the only real alternative when it comes to a modern browser on the desktop. I think the "my apps are dependent on a really old, non-compliant, and insecure browser" is tired and honestly a crutch. If your applications are so dependent on legacy technology the investment needs to be made to move them to more modern and scalable frameworks. Or abandoned all together, as is the case with Adobe Flash or Oracle's browser Java plugin.
One of the biggest strengths of the Microsoft ecosystem with Windows/Office etc is its backwards compatibility. But that being said, one thing really holding it back is to continue to bundle Internet Explorer with the operating system, especially with Windows 10. This would give Microsoft the power to say, sorry you should use a secure and modern browser to suit your needs and not have these security issues. Or, even better, point people to VM's or container based versions of IE. That way you don't pollute the base OS with old and unsupported technology, but giving companies who just won't invest in updating their systems the ability to use the older browser.