How much of this is driven by lumpy delivery? Tesla used to do this all the time: book thousands of orders, send them all over on a boat at once, then announce that they were the top-selling car in Swagistan (for that month, and no longer time scale). Is it the same story for BMW?
We're at the point where Tesla will stop being a near default choice as people realize they have other options. So we'll start to find out what their popularity really is.
The US has also been distorted by the charging network issue, but as more and more manufacturers get access to the Tesla network in the next few years that will cease to be an advantage too.