"All so easy to simply say too many cars, when the problem is really too many people needing to get about or needing services.....Things will get worse as more people are crammed into parts of London."
There's an implicit assumption that population growth or increasing economic activity results in more traffic.
That was not the case in London between 1999 and 2009 when population and GDP increased, but traffic decreased.
The ambition is to grow the economy faster, take in more people and actually reduce traffic, just as we managed to do for 10 years.
Public transport, particularly buses, does have a "too many cars" and other vehicles problem.
One solution is to provide more bus lanes and reduce lanes for traffic — that will both increase bus speed and reliability while reducing road space for vehicles which should reduce demand.
Increasing capacity for safe cycling will increase demand for cycling and act as a safety valve for economic growth, allowing more people to move about quickly without bringing the city to gridlock.
You complain that "very little supporting infrastructure is going in", but that's exactly what is happening — a modest increase in cycling infrastructure and a huge new tube line over the next couple of months.
There is plenty more that councils and city government can do to reduce traffic congestion — whether that's restricting traffic on residential roads, regulating Uber, introducing congestion charges / road pricing, providing incentives for home deliveries to move away from vans, setting up drop off points and lockers to help deliveries move to off peak times, providing infrastructure for shipment consolidation or taxing same / next day van deliveries and more.
However, if we want to enjoy roads that aren't choked with traffic and air that doesn't choke us, we are all going to have to accept some changes to how we live our lives.