I don't think at this stage the number of electric cars being made by other companies is the main threat to Tesla. The main threat is still convincing people that electric cars are a viable alternative to ICE cars, in which case the more alternatives there are a different price points then more people may be convinced to buy one, which actually helps Tesla. Ultimately, if there isn't demand on the level of ICE cars for electric, the Tesla is doomed with or without competition.