Funny, I thought it was the people who died or were seriously injured due to the bridge collapse who paid the highest price for the engineers’ failures.
The engineer, on the other hand, continues playing the iterated game of life, and so their reputation does matter (to themselves at least). Therefore, by making sure that any bridges that collapse has social stigma painted against those who designed and/or built it, it would encourage proper engineering even if there's no third party at the time to certify it.
> for the people who are still alive
The test subjects who are already dead don’t matter. GlaDOS, on the other hand, must continue to make choices in which experiments and test subjects will deliver the best bang for the buck.