It's a chicken and egg situation - until VFX houses (often with close to a million lines of Python code integrating stuff) need Python 3 (I don't see why they would based on the new features), they're not going to ask companies like The Foundry and Autodesk to add support for it.
And the commercial companies aren't going to waste dev (and huge amounts of test time) on a feature 95% of their customers don't want or need.
Houdini's got dual 2/3 support, but I find it very difficult to believe any big studio is using the 3 support (as it wouldn't integrate with the rest of the pipeline).
Maya 2012, Nuke 7 are on 2.6.4/5
Maya 2014, Nuke 8 are on 2.7.3.
It's a chicken and egg situation - until VFX houses (often with close to a million lines of Python code integrating stuff) need Python 3 (I don't see why they would based on the new features), they're not going to ask companies like The Foundry and Autodesk to add support for it.
And the commercial companies aren't going to waste dev (and huge amounts of test time) on a feature 95% of their customers don't want or need.
Houdini's got dual 2/3 support, but I find it very difficult to believe any big studio is using the 3 support (as it wouldn't integrate with the rest of the pipeline).