Competition in rail does exist in the UK and privatization turned around the network's fortunes. The ridership graph is very clear:

https://en.wikipedia.org/wiki/Privatisation_of_British_Rail#...

Traffic dropped a lot in the Great Depression but stabilized immediately after, and remained stable right up until nationalization in 1948 at which point the network entered a period of continuous decline, eventually falling to a level of ridership last seen in 1865. That is a staggering failure.

The moment the railways were privatized ridership starts going up again, despite the privatization not being complete and being unable to roll back the huge damage done under the decades of state ownership (before nationalization the railway companies were entirely self sufficient, which they no longer are).

So to argue that privatization makes "no sense" you have to ignore the fact that when privately managed usage of the railways goes up and when run by the state it goes down. If the goal of the railway is to be used, then it does make sense.