Actually many companies can and do wolrah
If you're producing widget x and have been for 10 years and you're making money today just as you were 10 years ago, sorry there is no "business need" to upgrade to all these bells and whistles of technology today. Does that fit the model of most, no it does not, but neither does updating to the latest technology every 3 months as some new fancy eye candy technology comes out. The choices of technology available today are almost mind boggling and the marketing and hype trying to drive everyone to update to the latest and greatest is probably one of the biggest ventures out there making money convincing you that you need to update constantly. Don't get me wrong - there is a need for some to update but not on this crazy endless upgrade/update cycle the computing industry seems to have settled on. If Microsoft and other software companies don't update and remain stagnant then they don't make money, so what do they do? They create new stuff and try to convince everyone they need it for one reason or another.
Back to the IE discussion though. As said, there are core systems created by Microsoft that are in place today in many companies that spent hundreds of thousands of dollars to get it all setup, licensed and working well. Now you expect or want them to be happy telling them to forget about that and update/upgrade to something more modern? Microsoft states that SharePoint has 190 million users across 200,000 customer organizations. Even their latest version of SharePoint 365 is old from 2013. For sake of argument, even if you spent the thousands of dollars to upgrade to the latest you'd still be on old technology that would not fully utilize Microsoft Edge in it's current state. What then, Chrome or Firefox again?