None of my four went to nursery - we lived in the sticks so there wasn't one, and therefore no pressure, but I wouldn't have sent them in any case. We saw other families a couple of times a week, so they did play with other children - but in our house/garden, or someone else's.
I don't understand why we're so determined to make little children "independent" and I think we're in danger of conditioning children to expect constant stimulation and structured play. I am amazed, for example, when I hear parents say their older kids get bored during school holidays - why on earth would they be bored?
We did do things together - playdough, baking, drawing and so on - but for the most part, they played alongside me, chatting, while I was busy, and then we all went for a walk, or to the shop, or to visit a friend, or to collect one of them from school or whatever. The days flew past.
It probably sounds very old-fashioned and dull to most of you but it was the norm back then - and it certainly didn't stop kids going to university and moving out into the big world later on.
Mine are now in their 20s and 30s, very sociable and outgoing. I'd have hated to miss that time with them when they were young; it passes so quickly.