Of course it might be reflected there. But Tesla is not saying anything to the line of "resale value might be lower than a comparable gasoline car because the battery will have to be replaced" either.
Interesting. But my original point stands: if you don't sell your car, you're looking at a $20k bill a few years down the line, and on the page Tesla are happy to talk about total-cost-of-ownership of their competitors, they're not telling you about that $20k replacement.
No reason to think it will be dramatically different from the cost now. With technology, the cost typically remains constant, while capability improves. The battery you need to buy in 10 years may be a lot better than the one you have now, but it won't likely be much cheaper.
This seems designed to prevent customers from following through:
During the period between 36 months to 39 months from your Guarantee Effective Date, you have the option to sell your vehicle to Tesla for the Guaranteed Resale Value. [...] This Guarantee automatically expires on the 39 month anniversary of the Guarantee Effective Date.
Why? If it's designed to be like a 3 year lease, and they give you a 3 month window to decide that, how is that a bad thing? It's strictly more flexible than a 3 year lease.