Yeah the problem with a Bakerloo extension is that it would abstract
revenue from buses and trains in the area so the sums dont stack up as
well as the (mainly) green/brownfield DLR which generates completley
new journeys with little abstraction from other public transport. (Only
exception being the line to North woolwich which will replace NR line
but I guess serving the airport tipped the balance here) However the
traffic along the Walworth road is now so bad for buses these days, I
think if the sums were run again adding in the congestion reduction
benefits we would see a better outcome.