you make many valid points. I would be, pretty sure, that would it not be for the Netscape developers, there would have been no Mozilla, and anything associated with it.
But, this was some ten years ago! Things changed since then. And, no matter who started what, the NS6 and 7.x were based on a Mozilla build. This happened after AOL had purchased Netscape. Indeed, I do have Navigator184.108.40.206, and, I will hang on, but not because it has some kind of Netscape label. The same goes for the excellent Messenger9.0, which never moved out of the early alpha stage.
I did not get my own computer, and, thus got to the Internet from home, till about ten or eleven years ago. At that time, my ISP, Cox, could set up a new user with either Netscape or IE. I chose Netscape. And, I had also been subscribing to AOL. When AOL decides, for good business reasons to rely on IE, I was done with AOL. And, Netscape never had any reason to be my primary browser, nor a mail client.
The only reason why the many vulnerabilities of Netscape, probably, hurt no one, is because the "nasties" would find little satisfaction in attacking Netscape. But, the fact remains that, especially, from NS7.2, and on, the programs were based on a Mozilla product, except for NS8.x.
Why a NS8 with a dual engine? Because Microsoft has been reigning supreme, and many website writer had no clue, or care little for anything but the dominant Microsoft programs.
Such web pages could be rendered properly, only, in IE. Thus, the need for a dual engine.
Many writers of webpages have done a good job making them compatible with the rapidly rising Firefox (upon which Navigator 9 was written). But there may be a need for some way to get to these pages, even now. So, there is the IE Tab add-on, which I use to download Windows Updates from Firefox (without it access would be denied).
And, the Mozilla suite has been carried on with the Seamonkey project. So, one has the option to get the NS7.2-like Seamonkey, which four years more up to date, or the standalones: Firefox, as browser, and Thunderbird for mail. Navigator, always, updated after
Firefox did, and Messenger, based on Thunderbird, went nowhere.
Do I see any need for Netscape? No! After so many years I don't see any good reason.
But, a name is very important to some. To me, the performance and security, matter more.
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b3pre) Gecko/2008010500 SeaMonkey/2.0a1pre