Sadly, you're right about the fire hoses.
I just saw an article on the front page of the Denver Post. There were numerous fire protection measures, but the fire rapidly climbed the "outside" of the building.
Sprinkler systems can be overwhelmed. Fireproof doors are useless if the apartments are catching fire from the outside.
Apparently, the building underwent a remodel, and part of the remodel was giving the entire outside an insulation cladding. Investigators are looking into whether that cladding conformed to fire codes.