At some point electric drivetrains and batteries will be available in large quantities from suppliers just like gasoline motors and gearboxes are available now.
As soon as that is the case, there will be many dozens of different car models that compete with Tesla.
Teslas vertical integration is an advantage now, because they don't have to wait for suppliers to develop what they need. But once suppliers have caught up, I'm not sure if Teslas edge holds.