After watching numerous interviews by witnesses it is clear that many victims could have made it down the stairs, but they were fearful of the smoke.
In particular a guy had prepared a rope made of sheets and had tied his daughter to his back! He said he wasn't going to die not trying to escape. He was on the 14th floor.
https://youtu.be/U8A8KgBV6J4
Fortunately Firemen arrived and told them to run down the stairs.
Whilst it's easy to throw forward alternate scenarios after the event, Fireman did make the call to evacuate, by my esiimates at 1.20 am, but they had no resources and no plan to lead residents down through a smoke filled stairway.
Apparently for around at least two hours (probably for the duration of the entire event) the radient heat on the fourth and fifth level in the stairwell was bearable.
Seems that the smoke extraction was ineffectual.
Even wearing BA, a densely smoke filled environment is a frightening experience, some people will freeze others won't. Once in starwell, navigation is not a problem.
Breathing filters, ogygen generators ect delivered to residents both by firemen climbing stairs and a few on call specialists (SAS?) dropped onto roof is doable using existing tech.
The influential folk working in highrise towers in the City of London are all ears.
Mjb