QuickTime has been abandoned by Apple for quite a while now. In Oct of 2011, with the release of IOS 10.5, QT became redundant Back in April 2016, Homeland Security recommended users remove it from their systems because it was no longer be supported, thus having many known security holes.
It wasn't until 2013, 2 years after Apple abandoned QT, that H.265 officially came into existence. In 2019, H.265 v7 officially came into existence. As of 2021, H.265 v8 was in the review process, but nothing I can find has mentioned it since then.
