Earlier quoted context omitted.
The biggest impact of WHATWG's work wasn't about features, but about defining HTML itself in a way that matched how web pages were written. Before HTML5, every browser parsed HTML in subtly incompatible ways. A document written for one browser could fail to render properly in another. Now, the process for converting bytes into a DOM tree is completely and precisely specified ( https://html.spec.whatwg.org/multipage/p…
> It's hard to overstate how important this sort of compatibility work has been to the strength of the modern web. There are fewer compatible browsers than at any time in the past 20 years. The compatibility problem has been solved by drowning browser maintainers in complexity and convincing them to give up. All the small browsers lack the manpower to implement the rapidly churning spec. This leaves the Google-funded…
Firstly, much of the complexity is an emergent property of interaction between a spec and reality: the engineering choices developers make when implementing a spec.
Pixel examples: (a) mitering of borders, (b) sizing four 25% width divs within a 99px div.
Pick just about any old spec, then look at the corner cases where developers have discovered different browsers act differently ("bugs"). The programming differences are often emergent and are not covered by the spec.
Developers create web pages that depend on the differences in a browser: that is a hard reality.
Secondly: Chrome mostly works better, follows specifications faster, and it is marketed better. Firefox has a significant budget, but it tools around with a bunch of shit that doesn't make their browser better. My interactions with Mozilla trying to get real bugs fixed have been poor. Safari and Microsoft were worse. Chrome cares about bugs, and fixes them in my experience.