It could be argued given the take up of Public Transport in London versus various other large cities that National Government investment is better made in Birmingham, Manchester, Glasgow etc.
In terms of TfL expansion, isn’t the real issue the other routes (Southern) etc don’t have the limited geographical spread that the existing TfL Rail routes have ? In terms of TfL levels of staffing, ticketing, service levels, it would be a huge change to take over any significant part of, for example, the Southern routes.
As for Buses and Sadiq’s performance, surely the real story is the general decrease in bus usage. Relatively minor at 0.7% (2017-18) in London, but seismic in lots of other parts of the country. One could argue in a London which continues to struggle with legally binding air quality requirements, that driving Diesel buses around empty is very problematic, and any rationalisation should be, at least from a climate perspective, welcomed.