Hub motors will be common on scooters and other small electric vehicles, but it will never make sense on full sized cars. The size of motor required to move a car with the acceleration and speed modern traffic demands just won't work in a hub. Reduction gearboxes and axle-shafts already represent a pretty tiny fraction of the total mass of drive units on EVs and there are no mass savings coming on motors that will somehow get them into the range of acceptable unsprung weight, even axial flux motors.

The whole industry is working on tighter integration of the drive unit components to reduce things like cooling circuits, length of high voltage cable runs, and the total mass of the components required to move the car. No one is working on splitting the motors out into the hubs.

As you point out, unsprung mass is bad. Especially for something like a motor it's beyond bad, it's a complete killer of ride quality and reliability. As sprung mass the entire drive system can be isolated from all the knocks and oscillations that happen from driving around. A hub motor will get crashed and bashed around and have a miserable MTBF. The occupants will hate the car since it will have awful handling and hitting even moderate-sized bumps will be terribly unpleasant. Lighter stuff like scooters can get away with hub motors since there just isn't that much mass to begin with, but cars are huge now.

Aptera is planning to use hub motors, but their car is the vapourist of wares and relies on being counted as a motorcycle under regulations. Their basic engineering just doesn't work when scaled to a 3500 pound car and beyond.