Let us hope that "ICT" is dead and buried
In an ideal world I would agree that we should be expecting 'the <insert subject> teacher' to address the big issues in their subject, whilst the Computing teacher has ensured that the children have the necessary level of digital literacy to be able to use digital technology to help them do so. However, I think that the competences required to use digital technology go beyond the ability to operate the technology, and incorporate what in the past we might have called ICT Competence (a broad set of knowledge (i.e. the ability to apply information), understanding and skills related to digital technology). Furthermore, whilst learning digital literacy 'in situ' (e.g. across the curriculum) would be better than having it as a discrete subset of Computing, in practice at present if it isn't explicitly specified in the PoS then there is a serious danger that it will not be addressed (or at best will be addressed inconsistently by different teachers).
Repeating what I have just written on another thread, I think the difference is between curriculum aims and pedagogy.
One of the great benefits of the new Computing curriculum, which I have been arguing for for a long time, is the disentangling of the teaching of technology and the use of technology to improve teaching. I think what we are discussing here is part of the second of these points. I don't think that technology changes the fundamental other subjects - but it does change the way that it can be taught and the fundamental learning contextualised.
Why do teachers not read the academic literature or research evidence? How do we stimulate a more vigorous debate (1) on pedagogy as a "design science" and (2) on ways in which technology can help that process? How do we stimulate a pull dynamic, rather than always relying on a government funded push? For me, those are the key questions.
We clearly disagree about the extent to which digital technology impacts on disciplines and should therefore impact on school subjects. Whilst we agree that what I've been calling TEL shouldn't be the focus of Computing (the subject).
However I think that digital literacy (my broad definition rather than the narrow technical skills definition) is different to both of the above things and does need to be taught as a discrete subject for reasons already set out in other posts in this discussion.
It seems to me that digital literacy is more important than computer science on the basis that everybody needs to be digitally literate whilst only a minority of folk need to be computer scientists.