Much of it has to do with Firefox's decisions in the past 5-7 years that have made it very unfriendly to enterprise environments. The provisioning tools have gotten progressively more hostile to IT departments.
The US government is also finally moving to more modern systems for authentication and Mozilla has incorporated some particularly poor changes to how the stack is handled that are very unfriendly to IT environments that need to manage credentials for multiple authoritative sources. We had to switch to Chrome a couple years ago because our support cases with Mozilla would on many occasions come back with a response of 'we've made our decision and will not be considering changes'.
Unfortunately, as Firefox kicks itself out of the enterprise market; that's going to cascade to the personal market even further as well.
First gen AH was great. I came to love second gen just as much. The reason I stopped watching was fairly pragmatic. I typically had RT/AH content running in a side window while I worked. However, I found myself unable to continue when they added Ky to the regular staff. She was funny, and fit the vibe check; but she had no compressor for her audio setup and it would literally hurt when she screamed or overreacted. As they increased her presence in content, I was left with less and less that I could watch. And when the community desperately tried to let RT know the volume spikes were an issue, it was very aggressively written off as the usual rabid 'fanbase' misogyny and racism.