> Why didn't Mozilla work harder to catch up with Chrome and counter Google? Was it a case of "My enemy's enemy is my friend?"
I'd argue that this "catching up to Google" was more their problem than their solution.
In making Firefox more and more Chrome-like they took away many unique and important Firefox features and they keep moving further and further in that direction. They now want to trash XUL and move to an extension framework that exactly matches Chrome's, removing the deep flexibility and customization that Firefox users have enjoyed. Several of my favorite extension authors have already announced they're giving up when that change happens.
If your browser just plays catch up without differentiating itself in any significant way, why would anyone use it?
Mozilla came up with some cool UI ideas, but never implemented them, or quickly did so, got them to a tiny percentage of their full potential and then abandoned them. That's the kind of thing they should be focusing on - that's the kind of thing that made Firefox gain market share in the first place. Instead they keep playing catch up. And playing catch up with a massive codebase against a giant company is incredibly hard.
Right now Brave is doing a better job differentiating itself and it's built on top of Electron - on Chrome's core codebase. If it were a little more active I think it'd have a shot at something.