There’s no easy comparison, however “equivalent” roles to CSS at other operators and TOCs would pay considerably less than this.
I hear this a lot in my working life and especially on social media, who often make the same claims. The answer is always the same - those individuals aren't being paid enough to afford even a miniscule home in zone 6, whilst at the same time being required to be physically present at their place of work in Central London. Their pay should be brought up, the race to the bottom argument is perpetuated by right wing media and business owners.
The fact that the application is going to be pulled earlier suggests they have lots of interested and probably perfectly well qualified external candisges. You can train systems, processes etc. but attitude is much harder.
The application was pulled after 48hrs and is now closed. Hopefully someone will make an FOI and see how many applications they got within those 48 hours. If I recall correctly, for a recent CSA campaign it was between 20 and 30k?
There is a slight correlation between quantity and quality I suppose, and I agree with you about being able to train people to an appropriate level. However like you, I also have concerns about a mass campaign to attract people who often won't have a proven record of working within a safety critical environment and wonder how TfL will be able to identify the individuals who will need incredible resilience to deal with the absolute loneliness and feelings of isolation in stations in far away zones. You can't teach those soft skills.
I do wish everyone success with their applications, but I suspect most will see the headline salary and not consider the drawbacks of this specific role (and indeed any role in transport.)