Why are your train fares so high?

Hi, looking at travelling to England later in the year and I was shocked by the train fares. £73 London to Leicester one way ! How are those costs justified? Is that what everyday commuters pay? Thanks

EDIT: Thankyou so much for the responses, I seem to have touched a nerve! I have downloaded the Trainline app and will look into the other links people have provided. What has come through though is how expensive even your “cheaper” tickets are, and the hoops you have to jump through just to get those.