Had to happen sooner or later. I just wish Microsoft had not tied Edge so deeply into Windows 10 (did they not learn from doing the same with Internet Explorer?) as at the moment it is limited to updates as part of the OS (Windows Update) and not the Microsoft Store.
I believe that is actually changing this month with the release of the Fall Creator's Update. This is very similar to Android, where originally core apps had to be upgraded with the OS, and were later spun out into being updated via the app store.
I think part of the reason for this is that you shouldn't be web browsing with old software. It's unsafe for you and others that your hardware could damage.
But apps should be update-able separately, not as part of an operating system update. That doesn't make much sense. Especially on mobile when you might want to only update single app currently relevant to you without blocking your phone for 40 minutes doing a huge update of everything. Also limited bandwidth.
I 100% agree, it does limit releases too...but they are changing this with the next Windows release. They are going to make Windows more modular too in the future.