OĶ, my last words on the suject seems to be ... rail employees ... resist change at any cost .... if it was good in Victorian times it is good now, and for ever more .... off to listen to my wireless .... good night.
That depends entirely what the change is. Crews are now using laptops and tablets, modern radio communication systems, train management systems and GPS for SDO aboard newer traction and so forth. Guards are generally based in publicly accessible offices on 390s, 450s and 444s, rather than the back cab or a brake van with a wind on / wind off handbrake. Drivers do not have a second man (except when safety systems fail), and in many cases are using modern DAS systems, and adapting to new traction.
The idea we are all going around flagging out / driving 47s hauling a rake of vacuum braked mark 1s with brake vans, having to stop at stations or signal boxes purely to speak to the signalman, and going on strike because a manager failed to knock on the newsroom door before entering and so on is a nonsense.
The reasons drivers do not want DOO have been summed up at length on here. To recap DOO is not a technological improvement, as that would assume that technology has replaced the need for a human to dispatch trains, evacuate passengers, secure the line and contact the signaller. It hasn't. Instead what it has done is put the responsibilities of the guard and platform staff on the driver. These responsibilities are safety critical tasks which if performed incorrectly, either by error or omission, can lead in the worst case scenario to death. The penalty for getting these wrong for a driver will be anything from a CDP (competence development plan) - which can affect future employment, through to dismissal, fines in court, or imprisonment (the legal precedent currently being 5 years).
It does not matter if the passenger is drunk, on drugs, violent, uncooperative, acting recklessly, engaging in criminal activity or whatever, the driver on DOO is solely liable for their welfare. This is on top of all the other duties a driver has to do deal with.
When DOO came in at first, it was largely on shorter trains with less passengers. The general attitude was that if you gained interlock at the doors, the train was safe to move, and in BR days at that time if you had a safety incident it was usually treated with no more than a slapped wrist or a dressing down, then forgotten about, rather than the endless paperwork, suspensions, demotion and so on. The general attitude in society back then also was that if a member of the public was acting in a reckless / criminal manner, then it was their own stupid fault if they got injured / killed.
Drivers were also promised other staff on board at the time (that did not materialise), and any risks with DOO were largely theoretical at the time, as no one quite knew what would materialise. Also the Serpell report had just been published, which recommended such drastic action as closing the entire Midland Mainline, anything west of Bristol, and virtually all regional railways routes, so there was a feeling of "desperate times call for desperate measures'. The drivers' pay was also dire at the time, so they were easily bribed - particularly as again risks were largely theoretical and there was a great fear the network could be chopped to bits. And even back then there was still huge opposition to DOO.
The pro DOO crowd like to tell us to "modernise" and that "we are not in the 80s now". I couldn't agree more. And this is why a discredited cheap cost cutting system brought in in 80s should be junked in favour of properly crewed trains, where the driver drives, the guard deals with the on train dispatch, passengers on trains and on board issues, and the platform staff deal with the station dispatch, issues on stations and passengers on stations.