I don't think you'll be able to browse any HTTPS websites today using Netscape (probably any version, not just something from 1994) — Wikipedia lists that as based on Firefox 2.x, and caniuse reports that doesn't support TLS 1.1 (the TLS 1.0 chart appears to be removed for being too obsolete).
Expecting the user to have a browser that supports a recent version of TLS is not unreasonable. My point was that even browsers older then most people imagine support HTTPS, but like you said something newer then Netscape would be required. If the argument being made though is we shouldn't require HTTPS to support users that use clients which don't support HTTPS, my question is still the same, what users and what clients?
Servers no longer support the old TLS versions, though. Or if they do, they get minus points on checks like this.