3.1 alpha 1 went out august 31st. Which was 7 months since 3.0.
This is the list of issues tagged for the 3.1 issue: https://github.com/godotengine/godot/milestone/7
With 992 open and 3950 closed, I'm guessing they've got a few months more of development. Some of those likely get pushed, but still quite a bit of work remaining.