@redskydarknight
I can assure you that elite ones do do this. The University of York (to pick one at random that sticks in my mind) must have had a huge marketing budget for their Open Day. There was an enormous number of people and resources involved; I imagine it takes the whole year to plan.
Whilst York is highly rated, I'd not class it as "elite" in the same was as Oxford, Cambridge, StAndrews, Durham, etc.
It's "competitive" as it's competing with the likes of Lancaster, Leeds, and Warwick, but they're not "elite", just within the top 10/20.
My son went to visit Oxford with his school and Cambridge on his own, and we went with him to Durham. It was very noticeable that they put a lot less "effort" into their open days than the likes of York, Leeds, Warwick and Lancaster who went to town on their open day facilities, tours, talks, etc.
It was abundantly clear that Oxford, Cambridge and Durham made less effort, simply because they don't need to. York, Leeds and Lancaster are basically competing against each other for the same "kind" of student, in terms of locality, entry requirements, league table places, etc., hence why they put so much effort in to get the best applicants that they can. Oxbridge, Durham and St Andrews are in a different league!