But is there the capacity on the tubes to take more passengers? What happens when there is a signal failure or other disruption on the tubes? Where is the resilience in the transport network?
A lot of the problem is the tubes aren't full like they used to be anymore, so they aren't making the money to subsidise the buses.
We don't run buses as a backup for tube failures and they don't do that in other big cities. In the event of disruption, the usual response is to get people to use other tube lines. Consider the £billions spent on tube upgrades over the last 20 or so years, plus the Elizabeth Line and Thameslink Programme.
Both these consultations are in areas affected by the Overground - the 259/279/349 parallel what is now the Weaver line, and outer end of the 38 has options to get to the West End via the Mildmay/Weaver/Windrush. Notably the proposed new number 10 ends just as it gets into the catchment area of those lines.
For all London's bus system is praised by politicians introducing franchising elsewhere, TfL don't appear to have any answers now bus use in inner London is in the same spiral of decline as the rest of the country. Just more cuts, usage declines further and repeat. As reported in post #3916 their efforts to arrest the decline in bus speeds are failing.