Yes, if we wanted a railway run like an airline or a coach service, then of course we could do it that way.Compulsory reservations would solve the problem of extreme overcrowding and people left on platforms, and enable yield pricing to spread the demand bulge out.
I will now retreat into my bunker and await the incoming
But if we want a country where public transport really can be an alternative to private transport, where people are encouraged to move where the jobs are however far that may be from friends and family, to go to distant universities rather than the one in the nearest town, or even to go 50 miles for a dentist appointment, then surely we need a good turn-up-and-go public transport service, inevitably subsidised as it is in other, more civilised, countries.
It's a choice — and much as British civil servants and the TOCs would clearly like the former, I'd much prefer the latter, even with the cost to the taxpayer (and it would be tax much better spent than on quite a number of things our governments (both parties) like to get up to).