In certain vehicle categories
In certain vehicle categories, it might be possible to argue that another manufacturer has the lead over Tesla by sales, but only because Tesla hasn't entered that segment yet. From a base of 20,000+ units sold, there's even a good chance that the Tesla Model X will beat out the Kona Electric or Niro EV in terms of 2019 sales. When you can't sell as many affordable electric SUV/CUVs at $40K as Tesla can sell luxury SUVs at $80-90K, you're not the industry leader in any meaningful sense. Right now, by production, sales, technology, and most other yardsticks, it's Tesla first and everyone else a distant second.