[erikj]

The complexity of the web platform is at least party to blame for this. The specifications for HTTP, HTML, DOM, CSS, JavaScript together are gargantuan and growing even further every year. This makes the development of Chrome's new competitors and the maintenance of already existing browsers extremely expensive, and it also hinders cross-browser compatibility of web applications as every browser fails to implement the monstrous specs flawlessly in its own unique ways.

[sjellis]

We are luckier than we deserve that Mozilla exists. If it was necessary to re-implement a modern Web browser completely from scratch today, it would probably take someone with the level of commitment of Richard Stallman to make it happen.