If you look on the
iOS history page on Wikipedia it states that iTunes 12.3 was not required until 9.2 so yes at the time those devices where supported on Vista. Nothing after 9.2 is supported... Since 9.2 was released last December that is why I stated that this really isn't a "new" problem...If you think about it Vista and XP users with newer devices have been updating their devices all year without iTunes support.
Regarding iOS 9.2, I presume that this is the sentence your argument is based on (correct me if I'm wrong): "Only supports iTunes 12.3 or higher, and thus does not work anymore together with iTunes on Mac OS X 10.7 or lower." I am certainly no authority on older Mac OS X versions, but I do know that Wikipedia doesn't necessarily attract the world's most careful encyclopedists (having made a few editorial corrections to Wikipedia articles myself), and I believe the sentence should properly be associated with iOS 9.0. I would edit the sentence myself if it mentioned Vista, but of course it doesn't. If you click the "iTunes 12.3 or higher" link within the sentence, it takes you to their
History of iTunes article, which states that iTunes 12.3.0.44 was released September 16, 2015 (concurrently with iOS 9.0), and "Adds support for iOS 9 and Windows 10." That might have been very bad news for those running Vista, since 12.3.0 was the fourth version of iTunes that did not support Vista (there have now been 12 such versions), except for one thing: The same
History of iTunes article states that iTunes 12.1.3.6 was released September 17, 2015, and "Adds support for iOS 9 for Windows XP and Vista."
If anyone who is actually using iTunes 12.1.3.6 on Vista to support a mobile device is still confused, they should probably consult Apple Support Community - speaking of which, there's an iTunes 12.1.3.6 user running Vista with an iPhone 6s running iOS 9.3.4 who is trying to upgrade to iOS 10.1 at
https://discussions.apple.com/thread/7668099.