The added funtionality that the browser "needs", once added, is in practice overwhelmingly directed at commercial purposes, primarily advertising-supported businesses.
In theory it could be used for anything.
Correct me if wrong, but Netscape was originally intended to be a browser for commercial enterprise where companies would pay licensing fees.
And Firefox, whatever its purpose was (perhaps an alternative to another corporate browser from Microsoft), ended up being the precursor to Chrome, a browser written by an ad sales company, as the original Chrome developers were originally Firefox developers.
Following the ideal that the web is this wonderful open platform accessible to anyone, I would like to see more browsers, with reduced functionalty (and perhaps increased safety/privacy and freedom from ads), written not by companies nor organizations that try to compete feature-for-feature with those corporations. These simpler browsers could target the non-commercial web, e.g. the web as a free information source. A web where an individual page need not be a conglomeration of random third parties vying for user attention.
Methinks it should be more troubling to the HN crowd that "browsers" are not amongst the class of programs that can be easily written, edited and compiled by anyone. They could be, but the popular definition of "browser" needs to change, moving away from "all the features of Company's browser" or "all the features Working Group is discussing with input from Companies" and more toward what a given user (cf. company, advertiser), including non-commercial users, actually needs for a given task.
There will always be corporate-sponsored web browsers with corporate-friendly, advertising-friendly features. But we need non-corporate browsers too. They may be enough to accomplish the user's non-commercial tasks but not well-suited for web advertising, e.g. optional auto-loading third party resources.