I feel like there may be something surprising. Like Dual Motor will be standard across all models, maybe except for S60. Wouldn't that just drive sales even that much more? That would be crazy and would further incentive the S85 and above... of course I don't believe this would happen just due to margins.
"don't appreciate the magnitude" could mean that
all Model S cars will be fitted with the dual motors from now on, just as the Model X will be. (initially there was going to be a 2-wheel drive version of the Model X)
This would leave the Model 3 as the only one without all-wheel-drive, which may not stay that way, or, it could go forwards with the Model S/X as the upper echelon product line that has all-wheel-drive as standard, but the cheaper product lines only offer it as an option.
Don't forget, Tesla are over 25% profit on cars at the moment... it wouldn't kill them to include the extra motor parts, and they'd get the cachet of all Tesla cars are all-wheel-drive. This would put to rest the discussions about dropping the base price of the Model S, etc..
And - if all the "Gen 2" cars (Model X and Model S) have standard all-wheel-drive, it would make things on the assembly lines easier, as you don't have to track dual or single motor manufacture.
Finally, and perhaps crucially, we are fairly certain the front motor is smaller and uses less KWh/mile than the back motor. And, that the rear motor is only used for heavy acceleration, the front motor doing most of the work inc. cruising (at any speed). Also, the contribution to "thrust" by each of these motors is very quickly and very smoothly controllable by the car's software such that you can't tell which motor/s is/are driving the car. Perhaps you end up using only the smaller motor most of the time? If despite the extra weight gain (75lb? 100lb?), the dual motor solution has resulted in MORE RANGE out of the same size battery, it would enhance all Tesla cars going forwards simply by including it. Elon is very much into that sort of ongoing improvement, plus, driving range is still a bugbear for electric cars (even the Model S) so any way to improve it would be of high value.
Perhaps both motors contributing to battery regen (via four wheels contributing, rather than only two), can somehow translate to more miles recovered through regen? (not sure of the engineering involved)
Better traction & safety, more even tire wear => life out of the tires, more driving range... no brainer!!!
If I am correct then
this could be the magnitude thing Elon refers to.
Bodes well for the pickup truck model that is mooted for down the road... you can bet it will be all-wheel-drive.
The only question would then be... what about the 60,000 rear-wheel-drive cars on the road, including mine... are they retrofittable?