I readily admit to not having read this entire thread, but, to answer the title's question:
There is a current examination (I don't think obsession is the right word) of the alternatives, as the TOC/NR operating model has proved not to work in so many cases, and the main alternative is a form of national(-ised)/integrated system. The fundamental issue is the tension between the provision of a public service and the generation of profit/returns for shareholders, which are mutually-exclusive. The concept of the national network for passengers (rather than that for maintenance) has been overlooked. This means that properly planned connections, timetabling, through ticketing, information consistency and facilities (among other things) have all been sacrificed for individual TOCs' own cost targets. The current privatisation model was based on the principles of competition and profit, neither of which are available in any meaningful way.
To compare any potential national rail network model with BR is inappropriate, as so many elements of the industry have changed so much. The problem may well be the difficulty in finding enough people to plan and manage the railway who have the experience and drive to make a properly integrated national system work well.