https://www.youtube.com/watch?v=9hw8Kzw60rE

Who was at fault and who should pay the bill?

The automaker.

They should have designed the driver side door handle to flash LEDs rearward if a hand touches the interior latch. This may give a cyclist the fraction of a second he needs to swerve, brake or otherwise mitigate the collision. Another light under the car should project an image onto the pavement indicating the zone swept out by the door as it opens. An alarm should go off as well.