I haven't been around long enough to give you a good answer. This is one of the worst events, possibly the worst residential tragedy in my lifetime (I'm 28 and happy to be corrected).
Fire brigade didn't get it wrong per se. With hindsight it's easy to say, but as mentioned previously flats are suppose to be designed to be self contained when it comes to fires. So standard procedure is to stay put, unless you are on the same floor. Allowing easy access for firefighters as often there is only the single stairwell.
Obviously something went massively wrong, and it looks like the cladding. Which appears to be regulation standard. Which would then mean regulations need to change. Which then means assigning blame is difficult.
Hopefully an investigation will uncover where the failings were. Was the cladding actually regulation? Or was it swapped out on the sly by the redevelopers? Was it manufactured correctly? Was the planning checked properly? Etc.