The reason why Brave can be Brave, is because it can hide under Chrome. Webpage owners will build their webpages Chrome-compatible, which makes them Brave-compatible, so whether they make any money off of supporting Brave is unimportant.

Mozilla can't do the same with Firefox, because they don't have anything to hide under. They rely on webpage owners making money off of Firefox, otherwise they're not going to build/test against Firefox.

Mozilla can be Brave with Firefox for iOS, and with Firefox Focus as well, because there they don't use Gecko as layout engine, they hide underneath someone else's layout engine. (Apple forces other browsers to use WebKit on iOS; Firefox Focus for Android uses Android Webview because it keeps the binary small, which is important as it's sort of meant to be a secondary browser.)

So, they're most definitely not doing the same for desktop and Android Firefox. It would kill Firefox/Gecko in no time, if they did that. It wouldn't be brave, it'd be suicide.

Apple has, well, courage to enable some anti-tracking features by default in desktop Safari. But of course Mobile Safari is so ubiquitous they know sites must continue supporting their engine.

Desktop also has tracking protection by default in private browsing windows. See Preferences -> Privacy -> Tracking Protection to enable it everywhere.

Per the roadmap at https://wiki.mozilla.org/Firefox/Roadmap, we're explicitly working toward making Firefox more opinionated in 2018. Specifically, "Firefox will take a stand against tracking," will "filter certain types of ads by default," and will "block ad re-targeting."

on android ff is by far the best browser for usability especially tab management ... chrome is a decided non starter on that OS

Switching from default Chrome to Brave on Android has been the best thing I've ever done on my phone.

May have to check out how FF compares

Brave is great but until they include dark mode I'll stick with Chromium from F-droid.

I'm inclined to agree. It runs beautifully on my Nextbit Robin. My wife however has nothing but problems with it on her Google Pixel.

They might just be looking for some way to differentiate themselves on iOS given Apple's policy of not allowing 3rd party rendering engines.

It looks like they want to turn this on incrementally. First private browsing, now this.

It gives web developers time to notice issues with their websites/webapps and fix/report them.

I would very much love it if Privacy Badger were included by default in browsers (or at least something with similar functionality).