That single reduction at the motor is not very important. Remember that there are many more gears in the car besides just the drive reduction! There's one gear mesh (spot where two gears meet) in that reduction, then
five per differential, of which there are two in 4wd vehicles. Even more importantly there are also eight CV joints[1] which have higher losses than gears, plus dozens of bearings and elastic losses in the wheels. The losses of the motor reduction are small compared to everything else.
Also, a single stage spur or helical reduction has ~99% efficiency[2]. It's not at all like a full transmission[3], which has a ton of parts that are always spinning and churning oil, plus sliding friction. The reduction on an electric motor uses a more efficient grease and does not churn oil. Fun fact- greases (mixes of soap and oil, normally silicone oils) are non-newtonian fluids. They're shear-thinning, like ketchup, and have much lower friction under pressure while still sticking in place, unlike oil. Amazingly sophisticated for something that has existed for centuries!
Anyway, what I'm saying in the above post is that even if the efficiency is much higher, even counting the gearing, it does not necessarily lead to higher efficiency elsewhere in the car. If this motor gives 20% improvement on an 85% efficient motor+gearset, that's only a 3.4% decrease (85/88) in power required. Say that 3.4% of power would have been operating in a regime that had 10% higher losses(which would be insane)- that's only .34% in cascading savings. 3.74% total. That decrease will be very, very easily overwhelmed if the motor requires higher current or is otherwise less ideal for the drivetrain. Resistive losses alone mean that if the current is 1.85% higher, it will be a net loss.
[1]: https://en.wikipedia.org/wiki/Constant-velocity_joint
[2]: https://khkgears.net/new/gear_knowledge/abcs_of_gears-b/gear...
[3]: https://youtu.be/vOo3TLgL0kM?t=779
