hsw fancy out a idealistic world where Firefox developers care about serious/old users, stay true to their Netscape legacy (which implies supporting several platforms and sound servers), and include native WebRTC support for SNDIO. The stark Reality,instead, is that they removed support for OSS/OSSv4 and ALSA in 52+ release, for RSS2/Atom in 60+ and stopped supporting Gopher and NNTP long ago.
So I use Seamonkey with OSS backend, and have all I need on it (a modern web browser, a FTP browser, a RSS feed reader, a Usenet reader, a Mail client, an address book, a HTML editor: the awesome SeaMonkey Composer) within less code bloat and 1/2-2/3 RAM requiements.