I’ve travelled a fair bit in Europe in recent years. In general you can get a decent sit down lunch with a soft drink for less than 10 Euro. The bigger cities are an exception but I’ve had a two plate lunch in Milan for €7, and a Pizza and a beer in Stuttgart for €8. Many small rural villages in France don’t have even a cafe nowadays but there are still the occassional ones. In the evening I would tend to eat out a bit posher - Germany is definitely the cheapest but I do go to quite a small town there. In most countries unless you go really upmarket you’re generally talking about a main course for €14 and no ridculous over charging for sides, if you just want a glass of wine or a bottle of beer you’re generally talking 3 - 3.50. In Dublin a main course in an equivalent place would be at least 20, most are around 24. I generally eat seafood which is usually cheaper in Dublin. Good meat is expensive in Europe but still not Dublin prices.
In Dublin a sit down lunch is usually at the very least 12-14 (somewhere like boojum can be less than a tenner but there are places like that for the same price or less in Europe). Although people don’t generally drink at lunch here.
If you look at the price of a big mac across France (4.69), Germany(4.35), Italy(4.52) and Ireland(4.54) you find very little variation and Ireland is in the middle.
That lack of variation suggests that the difference is not really in cost of materials (including taxes) , wages etc. although the very high turnover in McDonalds probably keeps costs down.
Even the supermarket cost of wine (https://www.numbeo.com/cost-of-living/country_price_rankings?itemId=14&displayCurrency=EUR) France (7.00), Italy (5.20), Germany (4.99) and Ireland (10.00) isn’t too different and I do remember reading that the markup on wine is similar in France and Ireland - however my experience tells me differently. Expensive wine generally costs the same in Ireland and France but everyday wine is a lot cheaper so the 7.00 bottle in france is seldom charged at more than 10.00 but in Dublin you won’t get that 10.00 bottle under 20 so the price markup in Dublin (10) is more than 3 times that in France(3) . If people go out for a meal here they also usually have a bottle each - in France and Italy they’re a bit more moderate. In Germany they’re too mean to stay drinking in the restaurant - they ususally go on to a bar after eating!
Restaurant rents are very high here - partly because of the history of restaurant failures and the problem of voids - once a place has been kitted out as a restaurant it’s a pretty expensive job to change it to anything else. Restaurants tend to be a vanity thing here as well - they all think they’re superchefs and sometimes they’re supported by money gained in some other way - they think that by charging higher prices they’ll get more kudos - unfortunately it works - the Irish are just not price concious enough.
In France and Italy (probably Germany as well) restaurants are family owned and run, they’ve been in the family for generations - there is no one holding their hand for rent. I eat in a couple of family owned and run restaurants in Dublin - they’ve been there for years - I’d say they make hay in the good times but they manage to ride out the bad times , their customers are faithful. I’ve used a few of them over the years and they gradually die off - they don’t seem to transcend the generations very well so its not quite the same as the continent.