How do you know? It's was unprefixed already ~3 months ago, so why should it happen with the next release? And when does the next release come? And why do their release cycles are not as short as those from Chrome or Firefox?
Because it's not their core business.
> ... to be lack of contributors on WebKit's part than anything.
Exactly what I wrote: Apple is focussing on other stuff than the web because—again—it's not their core business. They have two browsers, mobile Safari and desktop Safari and none of them got this important upgrade yet. A fast innovating web isn't in Apple's favor.
It was unprefixed ~6 months ago.
Their latest Safari release tracks WebKit release 600 which contains all changes until July 2014[1]. The latest WebKit release is 601, which contains all changes until September 2014[2], including the flexbox unprefixing. Safari normally update WebKit to the latest release in a non-maintenance update (e.g. Safari 8.1) so it should be available with the next release.
Another thing to note is that their Web Inspector (which is built with HTML+CSS+JS) already uses the unprefixed flexbox in trunk, so if they want to ship the updated Inspector, they will eventually have to ship the feature anyway.
[1]: http://trac.webkit.org/export/180623/tags/Safari-600.1.1/Cha...
[2]: http://trac.webkit.org/export/180623/tags/Safari-601.1.1/Sou...
2012-08-31 Tony Chang <[email protected]>
Remove ENABLE_CSS3_FLEXBOX compile time flag
https://bugs.webkit.org/show_bug.cgi?id=95382
[..snip..]
Everyone is already enabling this by default and the spec has stablized.
If so, as a honest question, I'm not sure how is this comment related to, or why should it be an example for Apple not being transparent about why they lag behind. Can you clarify?
Flexbox has been unprefixed in WebKit r173579[1][2]. Presumably, it will be available when Apple release the next version of Safari. Reading the Bugzilla, the reason of not unprefixing the feature seems to be lack of contributors on WebKit's part than anything.
[1]: http://trac.webkit.org/changeset/173579
[2]: https://bugs.webkit.org/show_bug.cgi?id=98420