I also think we have to appreciate how much ALL school marking has changed.
When I was a child, my writing was marked with something like a 'Well done' or 'Well tried', and with spellings corrected. None of what we would now describe as 'formative assessment' e.g. commentary on vocabulary, sentence structure, composition; no next steps.
Now, I mark every piece of writing done by a pupil against a set of specific success criteria, which they know and which they also assess themselves against. I identify, throughout the writing, where they have met each of these (e.g. use of complex sentences, or ambitious vocabulary, or modal verbs), and also where they could have done so but didn't. I then write two formative assessment comments, one substantial positive one, commenting in detail on what they have done well, based on the success criteria, 'next steps' from their last piece of work and also on longer term targets for that child. I then do the same in a 'next steps' comment, pointing out what they could have done better, and what they need to work on next time.
I do also mark their spelling mistakes - specifically mistakes in words from the spelling curriculum up to that point (e.g. common homophones), and common words that I know that specific child should be able to spell (so I mark different spellings in the work of an able speller than I do in the work of a child who struggles with spelling - the former might get an ambitious word that is wrongly spelt corrected, whereas the latter might only get common high frequency words corrected).
i am expected to do this for EVERY piece of work, overnight, for every child in a class of 32. I am also expected to mark all maths overnight (tick, cross, dot for correction, success criteria assessed and formative comment) and science / topic / RE / whatever other written work has been done that day as well.
This is VERY different from the marking of a generation ago, (and IME VERY different from secondary, where marking is relatively infrequent and MUCH less in depth). If the belief is that every spelling correction should be marked - and I agree that there is an argument for this - then the formative aspect of marking, and commentary on other aspects of the writing, would necessarily have to be reduced, simply to make the marking of 60 - 120 books per night, every night of the week, humanly possible.