IIRC everything except Edge and Safari are forced to use Silverlight for Netflix streaming. I'm not exactly sure why this is, but it probably has something to do with the mess that is video codec licensing.
Chrome uses widevine (DRM) for Netflix which uses HTML5. Really the more significant difference is that Chrome gets capped to 720p. Edge actually gets the 1080p streams (as does IE11 on Windows 8+ and the Netflix Windows Store app).
Your guess is as good as mine. Blame Netflix, Microsoft or the people pushing DRM. Maybe it's some combination of all of the above or none of them. I'm not sure anyone really knows why we have this behavior.
It's not necessarily DRM in HTML5 which is the issue here although I suppose the fractured nature of it may be partially to blame. It's the fact that it's seemingly arbitrary that Chrome gets capped to 720p and no one knows why. Did Microsoft pay a big chunk of change to Netflix for exclusivity or something along those lines? Do the content creators prefer Microsoft's DRM implementation over Widevine's?
Netflix plays fine in Chrome (maybe Firefox too) using HTML5, it was opt-in at one point not sure about now. I watch in Linux all the time, no Silverlight there.
Starting with Firefox 47, it works fine as well (macOS here), but you need to switch your user agent to Chrome (before you go to Netflix). I'm guessing Netflix hasn't updated their compatibility checker.
