When I was at school a residential in year 6 was standard.
What has changed is the price. I paid ten times the price for dd1 to go last year as was paid for me 30 years ago. To put in in perspective-her pocket money to take was roughly twice what iIhad.
The reason, as far as I can tell, is the rise of the "experts". When we went. It was a lovely old manor house with 3 resident adults.
As children we did the laying of tables, washing up afterwards and some of the cleaning at the end of the week, including changing the sheets for the next people.
What we did when we were there was: day 1: Country walk around the area. Days 2-4 depended on what group you were in. One of those days was going round the local castle and shopping area with a set of historic questions. One of the days was an orienteering course that was set up-we were set off in groups of 4 with a map, compass, lunch and instructions and expected to get back. And the other day was an "activity"-mine was going down a lead mine, but others did caving or mountain biking. Day 5: Tidying the house and packing followed by a sing song. We had a great time, and it was considered by many to be the trip everyone waited to be old enough to go.
What dd1 did included: Canoeing, dry slope skiing, abseilling (other similar things I can't remember)... all things that really need more supervision, and definite experts for each, and specialist equipment.
Did she enjoy it more?
I suspect she would have enjoyed what I did more. She's not desperately into there "extreme" sports, and her, and I suspect others, would have enjoyed doing some things that aren't really geared for the sporty ones. I think that her,. and some others I know, came back a bit flat, feeling that there was more to a trip than dashing round from one activity to another.
They didn't do any work round the place, and we even had to provide sheets and duvets/sleeping bags for them to take.