One of the main problems with Firefox is they have put in next to zero effort to making it nice for enterprises to deploy and manage. Sure there are third-party group policy templates and you can get special builds from other sites with commercial support etc but Google and MS give you that free and properly maintained.
I like Firefox personally and use it. But I don't deploy it to users as a first or even second choice as that's just going to generate work in maintaining and support calls.
If Mozilla don't get this, that users get familiar with what they use at work and then use that at home they are failing to understand people.
The home user was always very relevant but it's a changing environment. I would be sad to see Firefox end up the shambles that was the demise of Netscape Navigator.
Edge is just not finding a place. It feels kinda beta and is not cohesive in the way you would expect... is there even an Edge for mobile devices? Edge is probably better described by what it isn't than what it is. And that's a dull place of forgotten IE icons burried where you go as a last resort after you try chrome and firefox. Probably for the 5 people left with a Lumia or windows phone but I've yet to see it on Android. Firefox is there, it may be far from the usage of Chrome on Android but at least it's there at all.
Edge and plugins is something they need to sort out fast. No plugins is a death knell for many home users.