A) you're speculating
B) you say it's Woody's loss, and 'obviously' so, too, though you don't write that you know a damn thing about if there's a loss or not.
Do you have trouble with logic? Because I believe your entire comment is totally ridiculous. You come to a conclusion based upon something about which you are only speculating.
You might as well have speculated that the reason might be that she has ten ingrown toenails, and that they hurt too much for her to work.
Have you ever considered that there just might not be fitting roles for her, at least in Woody's eyes, for her to play in his recent movies? I sure haven't found any of the female roles miscast.
He just keeps getting better and better. And I'm glad he's happy. I hope Mia is happy, too.