Ill outline a few reasons why its rarely seen at Irish Exhibitions, as someone who has sat on organising committees. Some examples might be seen as extreme but everything needs to be taken into account. Its not just how one person might see it
Space - its limited. Would you rather see a very high standard layout or a table selling weak tea,cold coffee and stale scones and sandwiches
Litter - besides discarded cups and wrappers, droppages and spillages are not needed. Given todays litigation society, a discarded sandwich or spilled coffee is seen as bad as the proverbial banana skin
Health and safety - your in a public place and often in an area that is not being used for its intended purpose. Is there a risk assessment for that coffee machine on top of that school desk? What happens if its proven people got food poisoning after the same knives/chopping board was used for both raw meat and cooked meat? Some voluntary weekend staff might forget they are making food for public consumption
Staff/Resources - most shows in Ireland provide catering for the exhibitors only. Sometimes this is provided by the organising club and it could be the other halves of members. Occasionally a catering company will be brought in. Often the resources are not there. Mrs O'Reilly makes lovely sandwiches and scones but she might end up giving you the wrong change without the slightest notion. She might not be used to dealing with complaints either. Also voluntary catering staff cant be expected to work all day
The Market here does not require catering. Plenty of shops and restaurants near the vicinity of the show. Blackrock is 2 mins up the road
In short - the demand is not there, not to mention everything Ive outlined above