To get real nitpicky here, a number of EVs still have a multi-gear transmission. It's just 2 gears instead of 6+ though. You don't have to worry about staying in an efficient RPM for electric motors, but the torque multiplication factor of gears is still useful & can be necessary.

> To get real nitpicky here, a number of EVs still have a multi-gear transmission.

The number is like 2 or so innit? Audi and Porsche have a low gear for increased torque. Rimac's Concept One had a two-speed gearbox, but Nevera (formerly C2) dropped it. Formula E cars do have 5 or 6 gears.

> they have uniform torque over the entire RPM span

That's not true, electric motors make peak torque at low RPM and then it drops steadily with increasing RPM.

But yes, it's acceptable enough to allow for single speed transmissions for most road cars.