I didn't take any of our 3 dc to playgroups, nursery, or preschool.
They did go to soft play though for parties and with friends but only occasionally.
All of these situations have benefits to children and they prepare children well for school.
They aren't the only way to meet their needs though, they aren't necessary, unless of course you need the childcare aspect.
Ours are 23, 20 and 11 and have turned out/ are turning out fine.
I made sure they socialised, I read to them and they learned through play. We went to parks, shopping etc. We baked, watched tv, gardening, splashing in puddles.
It was lovely spending this time with them, watching them turn into the children they became.
They all 3 started school without any problems at all and in some areas were more independent.
Just make sure to give them time to be bored, to have to find something to do.