It's a combination of both. The only difference is usually easy chicks in big cities are hwores, where as in small towns not so much..i just got turned down in this little town i was passing through. i was having trouble finding where i was supposed to go so i asked this woman for directions then i asked if she had a bf. she said yes. she also seemed to be helping some older lady who was with her. i should have smiled and asked her for her number anyway but i didn't at the time. oh well.
when i was getting ready to go she pulled up beside me and asked if i was trying to get to my gf :) i wasn't but i do have one. i just didn't think it would hurt to try. idk why i didn't ask her then.
but it seems like getting girls in bigger cities is a lot easier. it seems like more of them are single, and even if they aren't it doesn't really matter.