Any potential competition for Tesla is going to run into at least 5 problems. There are many other problems other automobile manufacturers will encounter, such as legacy costs and contracts, but these are things that would probably be the most difficult to overcome.
1) The Model 3 will be released in 2017. Model 3 variants will probably be released in 2017/2018.
2) Permits for charging infrastructure.
3) Tesla's chargers are free. Tesla's competitors are relying on charging infrastructure produced by third parties, and charge to use it.
4) By the time any other company is able to match what Tesla has today and is ready to deploy the technology (assuming it ever happens), Tesla's vehicles will already by able to receive a full charge in 10-20 minutes, and Tesla will have Superchargers and destination chargers blanketed across every country.
5) Costs associated with maintaining and servicing legacy vehicles.