This supposes there is capacity to increase frequency. For almost all lines in London frequency was already at max. For example the Victoria line trains run e

This supposes there is capacity to increase frequency. For almost all lines in London frequency was already at max. For example the Victoria line trains run every 100s (it's actually harder to get faster than that) at peak times. Despite this the line is always completely packed (often waiting a train or two to get space) at peak times. Similarly on some routes it's a continous line of busses so capacity can't be added there either. Additionally stations that required lifts (elevators) can't increase capacity. Now during Covid capacity was reduced but it's being ramped up again. In London there is physically no way to physically distance people using public transport. The only way it'll be achieved is to get everyone who can walk or bike to work to do so. From my experience only a tiny fraction of the number of people who could bike to work did so. Now the offices are too small to physically distance people anyway so there are issues there too.