This is great news! I'm happy to see Tesla endeavoring to sell older cars themselves rather than simply getting rid of them at wholesale.
Months ago on another thread, I suggested that offering a lesser warranty on older cars might make sense. However, I'm not sure I understand the reasoning behind the fixed cap of 100K miles. If a car comes with 95K miles, then the customer experience is likely to suffer if the warranty expires after only 5K miles, as that may not provide enough time to "shake out" pre-existing issues with the car. And what about good cars with over 100K miles? Perhaps a floor of, say, 12K miles on the warranty might be better.
On our pre-owned 2012 Model S, for instance, the pano roof turned out to be leaky at roughly 75K miles. This became evident after a heavy rainstorm, when we noticed water damage in the headliner. Thankfully, even though Tesla had sold the car to us "as is" with some minor cosmetic damage, it did come with the pre-owned vehicle warranty and our Service Center was quite proactive about fixing everything. With over 90K miles on the odometer, a greatly abbreviated warranty, and a delivery date at the beginning of California's dry season, however, such latent issues might not become evident until after the warranty expires.
In any case, a selling point of EVs is that odometer mileage doesn't generally matter as much as with ICE cars. For the good of the Tesla brand if nothing else, I think that even the highest-mileage pre-owned vehicles should come with some minimum amount of warranty coverage when sold to retail buyers.