Safari doesn't compare with how IE was in its heydays.
In IE times, it was the majority browser and web shops were complaining that they were developing on less popular platforms (typically Firefox, and Netscape before it) and then ranting about how IE did things differently. Had they developed for IE all along with an aim for compatibility with FF, they'd have done things differently and, in many cases, compatibility wasn't that hard if you targeted lower common denominator - that is, a few earlier versions of each browser.
Sure, you'd miss out on the latest browser features, but that's not what web dev was about then. Rather, it was - depending on the shop - about making a site work on all platforms, or about making it work on IE and to hell with other platforms - with great despise from the rest of the community.
For some reason, things changed in recent years. Chrome is now dominant, and for whatever reason developing against its latest version has become the new normal, with web shops complaining that other browsers aren't keeping up fast enough, and no echo chamber to counter that discourse by pointing out that "hey, why aren't you targeting older browsers to begin with?" In case it needs reminding, iOS 7 is from 2013 and iOS 5 is still running on 2010 devices. That's only a few years ago. For comparison, we coped with IE6 for well over a decade, and XP (from 2001) only recently got deprecated.