Trendy?
A. Netscape, back in its prime, was the first to properly support CSS, which some sites required. That's not trendy.
B. Opera was never trendy, nor even popular. Its only real success was the mobile market, which has now been rendered irrelevant by smartphones fast enough to handle full size websites on their own.
C. Firefox wasn't trendy, and there's a reason it has such a massive marketshare nowadays. Until IE8 rolled around, using Internet Explorer was simply asking for trouble, and let's not forget how infuriating the lack of standards support in IE6 was. Transparent PNGs? Broken box model? Cherry-picked support of CSS2?
D. Chrome came around about the same time as Safari went to Windows. I don't think Apple expected that at all, and now Safari's usage on Windows is pretty laughable. Let's not forget the whole "installed by default" fiasco in Apple Updater as well, on Windows.
Oh, and to finish, Safari on OS X is insecure, Mentat. Period. IIRC, it was used to break into OS X on numerous occasions on security testing of Windows/Mac/Linux platforms. Just because you haven't had the issue yet doesn't mean this isn't true, or something to concern yourself with. That's like saying "I live in tornado alley, but I won't worry myself about tornadoes until one tears my house down."