Actually, the venue in very hilly and forested Golden Gate Park is surrounded well beyond the music venues by temporary tall steel wire chain link fencing to discourage quality free listening. As for the dense concert crowd, that never bothers me as long as there are open areas which there were, though such is impossible to see from the photo low camera angle.
Most concert goers today tend to focus their attention on watching musicians play. As a short person often blocked in crowds by standing taller others that has also never played musical instruments, as an adult, have always been more interested in listening to whatever live music and dancing. In the earlier era, rock concerts in our region never had seating in front of stages, thus people were all standing.
I strongly dislike seating in front of rock concert stages that arose later. And am not one to dance in one spot but rather wander about finding wider open spaces to do so. That also allows meeting others socially, versus being stuck in one place. Have a gymnastic skill of rarely ever touching much less running into nearby others, able to rapidly freeze stop, when any others approach too closely then continue dancing dynamically just as rapidly when space opens again.
At each side of the stage were huge screens. So even those way in the back could see the musicians. As a polo field, the venue is 1400 feet long so those in back would otherwise be looking at ants.