non-Mozilla Netscape has also been formally dead for several years now. It doesn't even have .5% of the browser market under its control.
I personally don't know anyone that uses anything less than Firefox 1.0, IE 6.0 or Opera 7.0. Nerd and non-nerd, I don't know anyone that uses an old browser anymore.
I have been using Opera 8.0 since it was released and love it. It's quite standards compliant and better IMO than Firefox, especially if you're a Mac user. Any Mac user should switch immediately from Firefox to Opera because it's almost as fast as Safari, but as capable as Firefox.
"I don't know anyone that uses an old browser anymore. "
It is still a large customer base for IE 4 and older browsers. I even know of a large corporate customer who refuses to move past Win98.