Agree with all that except the "filthy". That began to change in the 80s as BR finally realised that you do need to replace the upholstery more than once a century. They still weren't too hot about cleaning the outside of the trains but that came in its turn.
Privatisation: subsidy famously at three times BR levels for pretty much the same output; vast and massive bureaucracy bloat so that even the simplest thing takes bleeding forever to get done; visible signs of extra spending are visible signs of wasted money - lots of new rolling stock because (a) it's about the only thing left that's reasonably easy to do and (b) it enables them to shout "LOOK AT HOW MUCH MONEY WE'RE SPENDING ON THE RAILWAYS, AREN'T WE ACE", but as you correctly point out, most of it is crap. Uncomfortable, cramped, bad views, bad air quality, inadequate capacity (because the money has been spent on flashiness in preference to functionality), noisy and poor riding (because everything has to be a multiple unit). So the pleasantest trains on the system are the ones which remain from the 70s, like the HSTs - and now we are losing even those, for no good reason, and some utter knob jumped in at the last minute and kyboshed the hope that at least the IEP would not be yet another multiple unit. All that money should have gone into infrastructure, which is where it was needed, only they made that too difficult to do plus it's not showy enough. (Well, nearly all; I don't dispute that some new stock was needed, since first-generation DMUs were even worse than the modern ones, but a little more thought for practical matters, like what the stock is like from the inside, to actually travel in, in place of private-sector willy-waving over what it looks like from the outside would have been a massive help.)
And instead of the new stock being built by the nationalised railways themselves, it is built by private companies who take a profit off it and aren't even British.
If a nationalised industry is not being well run it isn't because it's nationalised, it's because the people running it aren't doing their jobs properly. The answer is not to privatise it and hope that magically fixes everything. It's a lot simpler than that: put a rocket under the arse of the people running it and tell them to pull their finger out, and if that doesn't work fire them and replace them with people who are prepared to do what they're being paid for.
If a nationalised industry can't function properly because it hasn't got enough money, the answer is to make sure it does have enough to function properly. Not to privatise it and hope the private sector will magically sort everything out. They will spend the money on the wrong things, and then make matters worse by wanting even more money back so they can make a profit.
The idea that privatisation saves money is simply nuts (and it certainly hasn't worked on the railways). To do a given thing costs x amount of money. To do the same thing and make a profit costs x + the profit. Therefore it is inevitably more expensive. The only way to make it cost less overall is to spend less on doing the thing, which in turn means that it won't be done properly.
And the whole idea that the railways have to make a profit is up the creek anyway. The roads don't. No reason why the railways should either. That they started off as private companies is not a reason.
Vital infrastructure, whether it's transport, water, medical care or whatever, is too important to be left to those whose prime concern is profit rather than service.
