Almost any tread wear warranty requires rotations (or is halved on staggered installs where you can't rotate). Presumably, if you had rotated you would have got 20k+ out of the set, since the fronts are still around half of the usable tread.
Some of my new cars have come with the manufacturer's tire warranty, others without. Presumably, it depends on the contract between the vehicle and tire manufacturer. In any case, the Michelin warranty requires rotation every 6-8k miles and wouldn't be valid.
The torque on Teslas will eat the tires if you're not gentle, my Model X got new tires at 13k miles and I'm close to needing replacements again at 25k. I'll at least get some prorated warranty on the 2nd set, even though I'm staggered and can't rotate (means the rear warranty is reduced to 25k).
Rotation is a must if you can do it, especially with the RWD.
EDIT: I won't be surprised if tire manufactures start specifically excluding EVs from tread wear warranties. The low end torque just eats them up.