Why did they not use reverse? Someone earlier stated that the stopping distance from V1 is calculated without considering reverse but it still seems to be a serious failure on the part of the crew. Just because the stopping distance calculation doesn't include the use of reverse, does it make use of reverse imprudent?
Still so much assumption. You're assuming that the crew made a mistake, or failed. How do you know that the crew was or was not able to deploy the reversers at all? Or the reasons? You don't. Therefore, to suggest that not deploying reversers or ground spoilers was a "failure" is an assumption in error, based on a lack of fact.
Wait for the facts.