To my knowledge, it was actually Google cloning the Australis interface, they just happened to release it earlier. And no, these UI changes were not made at th

To my knowledge, it was actually Google cloning the Australis interface, they just happened to release it earlier. And no, these UI changes were not made at the expense of fixing memory and performance issues. The reason why they didn't fix those memory and performance issues, is because it would have required introducing the (now introduced) multiprocess architecture. That would have required breaking all extensions (which is now being done with Firefox 57, along with breaking them to switch to a new extension API). So, that would have pissed off power users even more. And also just in general, you have to understand that power users are not that important for market share. They make up maybe 1%. If they bring their friends and family all along, then maybe 15%. There's a big number of users that are able to choose their own browser, but are not power users by any means. For example, around 40% of Firefox users don't have any extensions installed [1]. [1] The figure is from Sep 2015, but I don't think things have changed much since then. And if anything, the trend has so far been for this number to increase. https://bugzilla.mozilla.org/show_bug.cgi?id=1229949 https://bugzilla.mozilla.org/show_bug.cgi?id=1229949