Joost:

Wow... if that is true, then that is VERY harsh.
These guys gave it their all and have put down a stunning performance. The cars broke down after putting up such  fantastic fight.

BTW, on the track, the radio speakers were implying/reasoning that the 919s broke down due to the hybrid system regenerating too much energy. At certain areas, the hybrid system could not be charged further, so the energy needs to be dissipated in different ways (aka "brake discs")... not sure whether this speculation was correct though. I can hardly imagine that the engineers weren't able to predict how much energy regeneration was going to happen and create a car that can't use it's old-fashioned brakes alone.

One does not see this as being very harsh, especially when one considers the amount of capital, both financial and human, invested in the 919 project as well as the public relations effort undertaken.  Several rumors place the 919 project at over $200 million, and the car has had a comparatively long development cycle, with the car debuting in June of last year.  This time was to be dedicated to testing, testing, and testing with the desired outcome of reliability plus speed for the entire 24 hour period - Porsche is the crown jewel in the Volkswagen empire and expectations are set high.

Similarly Toyota, while fast, proved unreliable too.  Many factors are known about Le Mans and those factors do not deviate from year to year.  Audi, through preparation, pushed both Porsche and Toyota to the breaking point and this is very impressive considering that Audi #1 was built up over an evening just days before the race.