I think it’s awful that the subsidy is being removed. All the posters moaning about how they don’t get good or affordable services locally to them, so everyone else should have crap services.

That’s a rubbish argument. It’s not a race to the bottom. (better to write to your MP and council and support campaigns for better or more affordable services locally..)
There are factors relevant in London (a megacity) that are just different from other areas of the country, even the other big cities- very high volumes of motor and cycle traffic and people on pavements in rush hour and kids with big distances to cover to get to school. This is often to do with the immense cost of housing in London- these factors mean that not all children will be able to walk or cycle to a nearby school.
The cost of living can mean that parents struggle to provide a proper winter coat or shoes, it’s a ridiculous idea that they can suddenly stretch to a bike, helmet, and a secure lock, weatherproof and hi vis clothes to cycle in, all the rest of it. Schools don’t have showers available for kids to use after a long hot cycle journey.
Loads of Londoners can’t keep a bike anyway because of very small living spaces with common parts that must be kept clear, so nowhere to store a bike safely.
Also this isn’t just about school journeys- kids need to be able to get to places where they can socialise, do sports, get to a park, get to their part- time job, volunteer, engage with whatever public services are assisting them, whatever it is. Freedom to travel is such an important part of learning about independence, as well as looking beyond of your own immediate surroundings, all of these are really important parts of growing up.