It is a thin end of the wedge, for sure, but everything else is "questionable". This is not about profit, it's about government reducing cost. It's not a rush to the bottom of safety, it's about moving from one safe form of operation to another, albeit one possibly a little less safe. Statistically, UK DOO is safer than over 99% of the world's railways. What are guards getting blamed for that makes them scapegoats? Nothing that I can see.
This is essentially a dispute between DfT, presumably on behalf of their political masters, wanting to cut the cost of railways, and a group of staff who would like to keep their current job and T&Cs. Those of us who've been made redundant, or had their T&Cs changed, will sympathise. But when your time has come, it's really hard to stop it. Ask the coalminers.
The question is why have the government decided to pick a fight at this particular time? I think that there are two reasons:
1. All new trains are coming with on-board DOO cameras as standard; and
2. I suspect that digital ticketing advances are suggesting that ticket selling/checking roles will soon be unnecessary.
If I'm right, the gains are just too big. Trying to hold the tide back will be no more successful than it was for King Cnut.