What would the impact on accessibility be if all trains were DOO / DCO? If that were the case, only step-free stations which are staffed full time would be truly accessible.
Compare the last two options on the map below. The map shows what a devastating impact losing guards would have on accessibility across the UK.
I haven’t seen any reference yet to situations where a disabled traveller on a DOO train would cope with a bunch of drunk, lairy football supporters, or the like deciding to tip a wheelchair user out of their chair and then have races between themselves through the train? The driver will almost certainly be unaware, and in all probability any other passengers too scared to say or do anything.