So beyond everyone going back to a Neolithic way of life and living in a bunch of straw teepees all bundled close together, daycare is the best solution I've found to this need.
Just as an example, my oldest has been besties with another kid since they were both 7 months old.
That and we did take her out all the time. She just wasn't in daycare. The thing about stay-at-home parents is they don't literally stay at home all day.