Only read upto page 9 of the thread.
I think when the OP made the unfortunate "dead loss" comment, she was referring to the situation rather than the classmates, although I admit it doesn't read like that.
Do most of the classmates' parents in question work, OP? I think that makes a difference. If you work FT, or even PT, the work days are already arranged weeks in advance due to childcare issues, and on the work free days, parents are much more likely to want exclusive family time.
I can understand how you and your DD feel, the 6 weeks holidays used to drag and drag when I was a child, even though I had a friend up the street who I occasionally played with.
If there isn't a culture of playing out in your street, that's hardly a failing on your part. I would put my foot down though, and finances allowing, try and get your DD signed upto something a couple of days a week, and put your foot down for your sanity as much as hers.
My youngest 3 are currently playing Disney Infinity on the x-box, but I was your daughter as a child.