It's not available for newer cars like Model 3, Y...and 2021 Model S and X (production year, not the name "2021" that was produced in the fall of 2020).
See the reference:
The Extended Service Agreement covers the repair or replacement necessary to correct defects in the materials or workmanship of most parts manufactured or supplied by Tesla during the coverage period, excluding the lithium-ion battery and drive unit. Learn more about what's covered and how you...
www.tesla.com
It must not be worthwhile for Tesla or otherwise, it would love to continue that to the rest of the fleet and not cut the loss and discontinued after the last batch of 2020 S and X.
It sounds like there have been more claim expenses than the premium that they got. That may also be an alarm for those who think that EVs require fewer services.