Unless ocurrance reports have been raised by every crew that has even commented to themselves that 'mmm, that section of runway is a bit iffy' then no-one is to blame but those who have continued to use a clearly unsafe surface. Alarm bells have to be rung with airline, airport and regulatory authorities or nothing will ever get done. Being able to say 'it was an accident waiting to happen' and doing nothing to prevent it does nobody any favours.