In which case I apologise @stickerrocks & I see your point.
I don't know the answer other than there are those ( from Oxbridge & other universities ) - not me - but there are those who are involved in outreach programmes.
For those ( pupils) who do have the idea then they can access a good amount of very useful information on the various websites & if they have a desire to go to some good university then I am not sure at the stage they want to go to any university they couldn't look up their aspirational ones - take point re Oxbridge & I think medicine deadline Oct rather than Jan. But this is Summer before application.
I do agree with you that stuff like DoE , being a prefect etc should be done for its own sake - not because it looks good on a UCAS form - and for many universities this is just fluff and does not count. If these are encouraged unthinkingly by the schools - well ...... yes I see your point.
That said - if a pupil wants to say , go to Oxford to do history , there will be a presumption that that pupil has an actual demonstrable interest in history. For which probably reading will be pretty much it & if they have not naturally taken an interest , my guess is a bit of cramming over the summer holidays won't cut it. Other subjects will be different in terms of EC things on PS.
The thing I posted is more about the mechanics of making sure applications etc are put in on time , which is in many ways the easy part but but but I get your point that if you don't know it is a problem , you don't know how to address it.
There are so many people who try to do outreach work and explain these things. If the school doesn't know the basic timetable , not perfect ( understatement) - they should. I have a friend who has a nephew - his parents wouldn't even go to parents' evening , let alone help him with UCAS etc. Which was because they felt intimidated by the whole thing not through lack of caring. She (friend) bumbled her way through it with him ( she was not educated in the UK) - but school + websites & her effort have landed him some nice offers.
I do see why you are frustrated @stickerrocks - not sure there is an easy answer. Sorry my previous post didn't answer your question.