Optimize for latency of one class vs. optimize for total throughput... Both are valid choices in different contexts... Welcome to network QOS management !

From the foot of the elevator people walking will reach the top faster. However, navigating from the back of the queue at peak time to the start of the escalator is often time consuming.

It would be interesting what the times were between those navigating the queue and walking up vs during the trial where everyone stands but the queue to the escalator is shorter.

This. Systems Thinking teaches us that optimising a small part of the system (walking up the escalators) can have unintended consequences (bottlenecks/queues elsewhere) that result in the time through the whole system to be slower.

People who stand and queue up do not block the people who want to walk. The queue leaves access for the people who are willing to walk.

Apparently you haven't been on the London Underground at rush hour. The escalator halls aren't long enough for an orderly queue to form on one side when a tube offloads its passengers.

The original problem they are trying to solve is a big crowd of waiting people develops at the bottom of the escalator, and since London Underground passageways are quite narrow this blocks back until the platform gets overcrowded, which is unsafe.

Then don't you think they should encourage everyone to keep moving instead of being lazy and standing there. Escalators, like moving walkways, are designed to move people faster, not for people to just stand there like sheep.

It turns out you cannot simply order people to do something they find inconvenient or difficult, even if it is in their best interests.

Do they have a parallel set of stairs next to them? That usually seems to limit crowding, since the bigger the queue for the escalator gets, the more likely newcomers are to just take the stairs instead of join the escalator queue.

Given the age of the system in many stations there is room for only two escalators. Further older stations are very deep resulting in extremely long sets of stairs.