The best data I could find shows a decline of around 25% from 2006 to 2023 in restaurant visits. However, a big portion of this is because of meal delivery which is more expensive than restaurants, so the cause is probably not mostly increased cost.

Other related things like concert attendance have gone up.

My take is that the main reason young people don't go out is not price, they often seem to be making choices that cost more when they avoid going out