You have zero idea how much engineering it takes to create a standards compliant engine and then maintain it. “And you don’t need half a fucking billion just to develop a web browser”. Technically this is true if you are willing to use someone else’s web engine. Firefox aren’t doing that, and it requires huge investment to maintain their own engine. There is a reason only large companies these days (Apple, Google, Mozilla) have their own engines. The actual browser part is tiny compared to the engine. We are talking about something the size of the Linux kernel or bigger, that gets far less contributions from outside sources. It actually makes perfect sense they are looking at starting other projects when you think that all other companies that do this kind of work need those other projects to remain profitable. Web engine development from my understanding does not pay. You get almost the same amount of money using somebody else’s engine as you do developing your own, yet one costs way more.
The fact Mozilla manages to maintain a better web engine than Apple’s WebKit only from Google’s advertising money is actually incredible. Did I mention Apple didn’t even start that engine themselves? It’s based on KHTML. Chrome is in turn a WebKit derivative. Firefox on the other hand actually comes from Netscape, and was first developed under the name Mozilla based on Netscape’s code. So Mozilla has put in more work than Google in modernising their engine.