So according to his reports he make this 10 sec scene 2-3 months
Not to be THAT guy, but animation alone can take a while, for example one second of hand drawn animation is about 24frames, that's 24 pictures someone had to draw just for one second of animation, unless they animate "on twos" which is 12frames per second of animation.
Yeah 3D animation isn't exactly the same but it still takes some time, not including the lighting and rigging and physics on top of that, or even the other poses and ideas he tried to storyboard that didn't end up working out. So yeah, 2 - 3 months "just" for that 10 second sneakpeak, but also for everything else that went into making that scene work.
I understand peoples frustrations here but I think people severely underestimate what goes into animation, especially from those who don't understand what animation actually involves, you see 10 seconds and think he just posed the models, dragged the legs over, clicked the "enhance wobble" button, turned the lights on, then hit render and then sat back on his ass with a smug smile for 3 months. Some of you think that, and some of you deliberately want to think that because it's fun to dunk on JM and some of you don't care you just want it now.