I think the underlying question is; do people have a problem with privatisation in principle, or is it just the loss of the "BR feel"? Would people have preffered a BR Plc or a Intercity/Network SouthEast Ltd as Cecil Parkinson wanted?
The model was driven by an ideological obsession with internal (on rail) competition that could not be made to work within the framework used - and then the loss of power, in 1997, of the advocates of that model but the lack of desire of the incoming labour govt to fundamentally tackle it, apart from being forced to tackle the track aspect. IE Blair would not bring it back to sttae control (too old labour) but not obsessed with competition in the way the Tories were.
If we had stuck with the ideas of the '92 govt then the question to ask would have been 'where is all the open access competition, and where is the structure to allow that - train paths etc?'
So competition got watered down tot he idea of competitions of the franchises and no more than that - which the 2010 govt stuck to even when the wheels were falling off.
It would indeed probably have been better to have had a BR plc or a sector based privatsed model - but with the regulatory regime that would have needed.
Also of course for peak hour / big city commuting - the competition is from the private car - not within rail
But some of this arose because Tory utility 'privatization model mk 1' simply create private sector utility monopolies - eg took a fair while before you could get a phone from anyone other than BT, or fule from anyone other than the ex state owned org. A bit like water supply still is - ands the Tories were open to criticism about that from their own ideological starting point.
In the context of all this the more varied rolling stock in the BR era is a bit of a niche issue, albeit important for this forum - but yes it was - partly of course due to it being a legacy of the 1955 Plan and stuff not being life expired until 30 years after - but the relevance of that being the Treasury having a long memory of all the money supposedly wasted in that plan, and them not wanting a repeat of that or any desire to had BR more of the same any time soon...
So ironic that privatization has resulted in massive levels of spend all signed off by the Treasury - but that's back to ideology - no politician is going to let their great idea look bad if all it takes to make it look less bad is to spend other people's money on such an objective...
I mean you only have to look at covid testing / track and trace / £50m of useless PPE etc etc to see that after all!