Without the exact Michelin model name, this is a little speculation. If you have 60K on them, then you can expect between 10-12K more and possibly 20K more. Many top of the line Michelins are “warranted” for 80K miles. That is how I can up with this math.
My own experience is that I have never gotten even 70K miles out of an 80K tire, particularly in the recent past. I tend to stick with 50-60K tires simply because I have had better “luck” with them, and tend to get the full warranted miles out of them.
If I get down to about 4/32d and winter weather is coming on, then I would consider changing them early. 2/32ds is not a good tread depth for winter in the midwest.