It's because of safari. Same problem used to be with IE where computers/OS were stuck with a specific version. Now the world has moved onto evergreen browsers which are no pinned to OS versions (except for Apple).
Safari is the new IE. From one point of view it's good that Apple still develops his browser and didn't choose to use Chromium like all the others (except Firefox), but from another to this day keeping up with all new web features and standard is not a simple thing. Safari usually is the last to implement modern web features.
> From one point of view it's good that Apple still develops his browser and didn't choose to use Chromium like all the others (except Firefox)
Technically, sure, and I'm all for browser diversity... but i'm kind of tired of this comment because Apple barely put any work or money into webkit while being excessively profitable (and there are good "business" reasons for them not doing this). At this point it's just not excusable for Apple... The way to support browser diversity would be for Apple to fund webkit properly rather than keep it on life support, locking their OS to safari is not the healthy solution for the web, it's the healthy solution for the App store's bottom line.