Germany subsidies its rail network by €17b a year. The UK subsidises by €4b.
In the UK we have decided to go for lower taxes and lower subsidies. We do that while still subsidising lines that are good for the country but not profitable (old mining towns in south wales which would collapse if people couldn't commute to Cardiff etc, cornish rurual lines which attract tourism and offer transport for local residents who may not have 1 car per adult, etc). This means that on the profitable lines which would make commercial sense (say Manchester to London, or some London commuter lines) we have to charge more.
Remember commuter tickets are twice the price of business tickets - as they are paid after income tax (which varies from 33% to 60%). When I was offered a job based in the office, I wanted an extra £10k a year for the commute -- £2200 for the ticket, £3300 for the extra tax to pay for that ticket, and £5k for the time out of my day. They decided that I didn't actually need to be based in an office after all, and I go (to that one) about once every 3 months, which costs them £20 return (but would cost me £45).
This is offset by the massive discounts. A season ticket from Nuneaton to London, 206 miles a day, about 1 hour in each direction, is £9000 a year, for 230+ days of travel, or 47,000 miles. 19p per mile. If you're willing to take a little longer and travel on London Midland it's £6500 per year, 14p per mile.
On the other hand, a day trip from Nuneaton is £154 in peak time, £104 on the slower train. That's 74p per mile - 3.5 times the price of the commuter.