It's too bad that many Greek churches don't have Vespers, because I love Vespers. However, if nobody shows up, that might be one reason for not having them. I attend an OCA mission, so they do tend to have them. For one thing, many OCA priests have confession after Vespers and many of them expect you to attend Vespers if you want to take Communion the next morning.
A little bit off the topic but reflecting on what Tom said about many of the younger people leaving the Church, there is a young man who posts on a board called Christians Unite (I don't post there anymore), who was raised Greek Orthodox but is now an Evangelical. He really mocks Orthodox beliefs on that board. There were several of us who were trying to lovingly defend Orthodoxy (though I think most of them are about to pack it in). He is going by the name Juan (though he has said his name is Peter), and you may want to keep him in your prayers. It is pretty clear that though he may have attended church that he knows very little about the Orthodox faith and the reasons behind our practices. Reading his posts on that board really showed me how important it is for those of us who are parents and godparents to take our responsibility very seriously to live our faith and to teach our young people about the faith. Also, if it's not being done, the church needs to make sure that the young people are given a class or something on their faith. Yes, they've probably been baptized when they were babies, but what's wrong with holding a "cathechism" class for them to teach them the things that a catechumen is taught. I am just praying that one day when Juan is older that he'll get curious about Orthodoxy and study to find out what it is really about.