Playing devils advocate........
Why should peak fairs remain high?
These are people who are contributing to the economy - off peak fairs are probably students/leisure/retired/unemployed - who didly squat in these hard times
Cut the service and subsidize the peak - make it easier for people to get to work
Yes, I can see your point, but fare drops at peak times would result in critical overcrowding, even at Finstock!

Cutting services off peak is not a good idea. Staff with nothing to do. Rolling stock lying around. Stations empty, but staffed or with
CCTV▸ and lights. Tracks maintained to the same level, but for less traffic. Would be a disaster.
The main reason for low off peak fares is to make commuter lines worth running. The mad rushes in the peaks may seem huge, but do NOT guarantee that a line makes profit, or even breaks even.
Beeching mentioned these issues when he reluctantly kept commuter lines open.