> If you live in an area that primarily gets electricity from coal plants

That's a rather extreme assumption. The article you linked to also gives the more representative figure of 14,800 miles for "U.S. average energy mix (23% coal-fired, plus other fossil fuels and renewables)".

To put things in perspective there are only 12 states that are majority coal powered (according to 2017 numbers[0]):

    1. West Virginia - 93.2%
    2. Wyoming - 85.7%
    3. Missouri - 79.8%
    4. Kentucky - 78.2%
    5. Indiana - 73.2%
    6. Utah - 70.5%
    7. North Dakota - 64.5%
    8. Nebraska - 59.8%
    9. Ohio - 57.2%
    10. Wisconsin - 55.1%
    11. New Mexico - 54.8%
    12. Colorado - 54.3%

Also, it's not unrealistic for a Model 3 to do 80,000+ miles. Some have already managed 100,000 miles[1], which is apparently the minimum warranty period too.[2]

[0] https://stacker.com/stories/3356/states-producing-most-elect...

[1] https://electrek.co/2019/10/21/tesla-model-3-100000-miles/

[2] https://www.findmyelectric.com/blog/how-long-does-a-tesla-ba...