That's usually done before selling a product, not afterwards, especially after they charged extra for the level of performance. If the level of performance is going to be reduced after the fact they need to a.) disclose that possibility before the sale and b.) compensate buyers who were not warned of that possibility before the sale. What happened is Tesla made a mistake, a big one, by pushing the performance beyond what certain components were capable of with a reasonable MTBF, and they charged extra for that performance. You are happy to give back some of that performance without compensation, great, your choice, but you should be able to understand that others are not.
If you bought a computer with a processor capable of a specific level of performance and then after the fact the company sent out an update which reduced the output to preserve it's longevity but offered you no compensation for the reduction would you be fine with that? Most would not if they could have simply paid less for a lower performing processor in the first place.