There's no magic technology, it's just a difference in design goals. FPV drones are designed for speed, performance and robustness, DJI drones are designed for duration and carrying a gimbled camera.

[Larger, slower turning rotors are more efficient at producing lift.][1] That's why helicopters can hover and propeller planes with the same size engine can't - but the plane is faster. Photography drones (such as DJI) use large rotors and exploit that efficiency for duration. Race drones use smaller rotors because they want to go as fast as possible.

The other factor is that photography drones typically carry larger batteries for longer duration, while race drones want to keep their weight down for maximum agility and acceleration. A photography drone will fly so long as it can produce more thrust than its weight, typically they have less than a 2:1 thrust-to-weight ratio and can't maintain altitude when angled more than 45 degrees from horizontal. Race drones can have a 10:1 thrust to weight ratio, and commonly fly at pretty extreme angles.

So long as a race drone has enough duration to complete the race, any extra battery capacity is just dead weight, slowing it down. For their pilots, changing the battery every few minutes is a small price to pay for the performance.
 

  [1]: https://drones.stackexchange.com/questions/961/why-are-larger-propellers-generally-more-efficient-than-smaller-ones