I'm not sure exactly how they define 'drove 1M miles" however this is the sort of wear (or lack of) Tesla wants you to expect after a million miles of usage:
“We are very happy with the quality of the drive unit. We changed the goal of the drive unit endurance from being approximately 200,000 miles to being a million miles – just basically we want drive units that just never wear out. That’s our goal. I think we made really good progress in that direction. the drive unit that are going out now and for the last several months have been excellent.”