Think of it as lock-in. Back in the day, pre-Chrome, pre-decent-Safari, pre-IE7, 8 or 9 you had IE6, which was stodgy, and Firefox 1.x
Firefox was fast, it had tabs, it had nifty extensions to make you go woo-woo-woo, and it was cooler. So people switched to it in droves, and got used to doing things with certain extensions, or just doing things 'the firefox way'.
That was how I was until I got my Mac. I had firefox on there for a few months and then got tired of it not quite matching the OS, so I gave Safari (I guess it was 3 at the time) a try, and it was faster, and leaner, and integrated better with the OS so i went to it full time. I was never an extension user, and never needed to open up multiple sites as my homepage, so Safari was fine for me.
And now I am locked-in on Safari, I prefer the look and feel of it.
