Three decades of having private operation in Britain for the whole train network only yielded higher prices and shittier service than the old public service.

Also every single one of the companies you listed there are public companies and that entire business model is only working because the State paid for the high speed infrastructure.

If you want to see what happens some years after the State stops pouring money into infrastructure, look at Britain again - the infrastructure is slowly decaying and trains are getting slower, with the exception of the whole Eurotunnel which is brand new, State paid, infrastructure.

Last and not least, 2 or 3 companies only caring about a handfull of high value routes is in no way form or shape sufficient competition to add up to a healthy competitive market (just look at how many airlines serve high value routes for reference of how real competition looks like and even there, there are barriers to entry - in the form of airport slots - that limit competition so it's far from perfect in terms of competition), not to mention tgat what you see in the main most profitable routes is most definitelly not something that you see in an entire network.