I remember how long it took to release a stable version of Mozilla and Mozilla Phoenix. In the meantime, had to recompile newer releases all the time manually. There was no alternative browser on Linux or *NIX for that matter (OK, macOS still had MSIE).
The successor of Netscape Communicator was Mozilla (IIRC it was just called that, later renamed Mozilla SeaMonkey), and the successor of Netscape Navigator was Mozilla Phoenix (later renamed Mozilla Firebird and eventually Mozilla Firefox). Firefox and Thunderbird were once again separate clients.
Mozilla was still considered bloated, but Phoenix was far less bloated which is nice on lower RAM machines, and allowed the start of Web 2.0. It was also the return of doing one thing and doing it right: browsing the WWW. As Netscape Communicator (unlike its predecessor, Netscape Navigator) came with a Usenet client and e-mail client.
Later in development, addons became a thing, and you could add features which were previously part of Netscape Communicator such as calendar, HTML editor, etc. You can also add such features with addons to Mozilla Thunderbird.
Then Google Chrome happened, and people switched to that, but I'm not entirely sure why.
