>How did Mozilla survive as a business?

On one end by almost literally being an extension of Google. On the other end by constantly laying off engineers. A big problem people are just handwaving away is that browsers are incredibly complex nowadays and how do you fund development of a browser engine? If you think the "Linux" model would work, well browsers already have that - it's called Mozilla and there is never any good news about them.

Brave is also funded by Google - Brave doesn't develop a browser, they develop a skin around a browser engine that Google pays millions to develop and has decided to open source.

Browsers are way more complex than OSs these days. Mozillas Servo project had over 40,000 commits and still wasn't ready for production and it was only a small part of the browser. I don't think there is anything else that could have 40k commits and still be a tech demo.

back in 1999 looking at nspr (Netscape Portable Runtime - the foundation of Mozilla) i remember thinking - it just can be packaged alone as an OS, similar to Java OS (which i had been working with before that our Mozilla project).

There is also another aspect to it - one can imagine that the time of an OS which would run web apps as first class citizens (in the correctly engineered sandboxes/etc.) just hasn't come yet. In the meantime the browsers are just ugly stop-gap 0.x version of such an OS (there is a reason they are "browsers" as their roots (incl. deep architectural roots) are in browsing of static content, and everything else is bolt-ons - the integration of JavaScript engine for example back then could be best described exactly as a "bolt-on").

Mozilla is financed directly by Google. Brave is injecting their own ads into websites.

Not really the best examples.

I've been using Brave on mobile and my laptop (currently running Pop!_os) exclusively for about six months now, coming from Firefox. Your criticism isn't accurate, Brave doesn't insert ads into pages, it gives you the option of receiving ads in your notification stream. If you choose to allow the ads you are compensated with a small amount of a crypto currency, which you can opt to have automatically distributed to the participating sites you visit. Wikipedia, for example, is a participating site. These micropayments offer the only viable monetization alternative I'm aware of to charging for access, selling user data, or including advertising on your page. I've moved to using Brave exclusively because I want to live in a world where the web is free to access but my privacy is respected and my browser isn't crowded with ads.

Honestly several of these guys just want to promote 'break google up' every chance they get just because it makes them feel good - without understanding how bad the consequences would be.

What would the bad consequences be?

One example: The road from security to revenue is a bit windy. So suppose chrome gets a revenue crunch after getting spun off, and lays off a bunch of the security group. Well, it turns out that security group is actually handling security for ALL of the browsers, because security is expensive, and none of the browsers are really making money, and chrome is open source. So now you've got reduced security in all of the browsers. Whoops?

Sure, could happen. Or maybe more of the relevant players share the load, the way they do with the kernel.

Brave does not inject their own ads into websites.

Brave is terrible example. Brave is vc funded or ICO funded. Mozilla depends on donations and selling the search engine slot.