I'm enjoying your input and can agree with much of what you say. Needless to say, pretty well all of the points you raise have been done to death on this thread in the course of the 6,600+ (!!) posts to date and you'll see that we have already managed a few points of general agreement (or at least a better understanding of where we may differ).
One point I would pick on would be your reference to job security. Naturally, it's highly important to the existing guards who may feel threatened by DOO/DCO but I fail to see why they have real concerns. The TOC has guaranteed no redundancies [I still bet they wish they hadn't done that !] for many years longer than anyone could possibly expect out in the 'real world' - and yet the RMT/members are still unhappy. What else can the TOC do but guarantee no redundancies ?.
I accept that, nowadays, there might be an increased likelihood of Arriva just despairing, and throwing in the towel, but that wasn't the case when the guarantee was made - and some of the damage caused since that time has been a direct result of action taken by the RMT [........ironic - but not enough for anyone to laugh about].
Specific jobs can't be guaranteed to never change at all (whether the RMT likes that or not) and there will be a need for guards on much of the older stock anyway. If, as you say, there is a high turnover of staff then it's even more difficult to see why it's necessary to have strikes all the time.