My son is currently at Winchester and is having the time of his life there.
I myself was a boarder at a different school 30+ years ago and certainly had a great time there myself.
We too had to choose between Eton and Wincoll and the large dorms instead of single rooms + house dining were two of the main deciding factors for us. I certainly believe in this day and age, if left to their own devices (pun intended), a few could retreat into their own shells.
One or two of my son's dorm mates do spend quite a lot of time on games and discord but it is by no means pervasive. There is just so much to do and not everyone is into gaming.
I've never really considered pastoral care an important factor in school choice. I've been through the experience myself and to me boys are boys and should be encouraged to fend for/take care of themselves. Only the overly protected would need any "pastoral care", most people get on with it. There is one student in my son's year group who is perhaps on the Autism spectrum that might need a bit more "care" and I think our housemaster/matron deals with it admirably. There are of course a couple boys that moan and complain all the time, and they are those who get pampered at home and have nit picking parents.
I am most happy with my choice. My son is the intellectual type and is just made for Div lessons and Wincoll life.
It may not be for everyone though, I agree.