Well I was at primary in the 80s and I do see what they are saying.
I went to a one form entry standard state primary.
Our teachers did loads of out of school activities-all free, I can remember offhand: ballet, gardening, comics, chess, football, netball, badminton, short tennis, rounders, drama, library, computer. They also used to organise Saturday morning videos for pupils plus siblings and three times a year a disco and evening concerts involving (sometimes) all the children.
We had a lot more flexibility in the time tables. For example through the juniors we did a lot of plays, we'd have one afternoon a week increasing to most afternoons just before we performed.
I remember our form getting excited about a programme that had been on the night before about wildlife abroad, and our teacher listening to the conversation at registration, and saying "Did you know we have lots of wildlife round here? If you promise to work extra hard tomorrow we'll go and look for it now."
And we got up, and spent the morning walking round the area collecting flowers and making notes on wildlife we saw, and the afternoon pressing the flowers and looking up in books what we'd seen. Educational-but would never happen today.
Or the time our teacher phoned the local farm and asked if we could come and watch milking time when we'd watched the cows coming down the lane. And we (infants) trooped across and were allowed to teach the calves how to drink milk from buckets. Totally spur of the moment thing,.
And the day we all walked down as a school to watch the mill chimney bening blown up, or when we found bits of an old plate in a ditch and were convinced we'd found an antique and the teacher allowed us to piece it together during class time.
And the day we spent orienteering on a residential. Set off in groups of 4 with a compass, instruction leaflet and lunch, no teachers, into the wilds of Yorkshire. Told to try and be back by 4pm.
Three of us taken down in the head's car to buy a present from our form (us having done a quick wip round-about 2, which was our money for the tuck shop) for one of the infants, whose mum had just died and we'd found him crying.
Yes, nowadays they do a lot of officially other subjects: History we did a little because one of the teachers was keen, but I never did any geography, science was the headteacher doing (big) experiments-I can remember every one of them, RE was sketchy, music was mostly done in year 4 when you had the music teacher as your class teacher.
I think that's what they meant. Our teachers listened to us, and if there was something we were enthusiastic about they'd take it further, I don't think there is the flexibility in the timetable to do that nowadays.