Why don't we have Friends on the Big Screen?

Which one are you most like, Joey, Ross, ahh, I got it, the Chan-Chan man. What about you, are you the anal Monika, the flaky Phoebe or the annoying Rachel. These questions are still in pop culture lore. One of the most loved TV series of all time, Friends set records for viewers, and for DVD sales, and I loved it, I mean, it jumped the shark (the history for that will be in the next post) with about 2 seasons to go, but I really loved the perfect comedy, the well placed drama and, especially the chemistry between the group, which is hard to maintain for so long with such a large cast. So, the question is, with the success of Sex and the City and the upcoming sequel, along with any other TV shows turning into movies these days, why is one of the best not the first one in line. Friends had a huge following, and spanned a large demographic, but why has that not translated to the big screen?
I read a possible reason the other day, someone said that people were used to seeing these beloved characters for free, and were not willing to pay to see them now. Yet another had stated it's because of terrible attempts at the big screen by its cast, and he was right, let's think of a few of the movies they tried to do.
Lisa Kudrow attempted Marci X, and Lucky Numbers; Matt LeBlanc attempted Lost in Space and Ed; David Schwimmer was in 6 days and 7 nights and The Pallbearer; Courtney Cox has done 3000 miles to Graceland, and Scream; you had Jennifer Anniston who got dumped by Bradd Pitt and Picture Perfect; and finally, my favorite, Chandler's Matthew Perry did Whole Nine Yards (which I loved) and Fools Rush In, along with Tango and Cash and Serving Sarah.
None of these movies have done anything, so has their track record turned off Hollywood execs from taking a chance, or perhaps has the story simply run it's course, and the creative minds behind the series simply run out of stories? The actors have all said they would be up for a movie, given the right script, so, let's get the gang back together to save the world from an atomic bomb, or perhaps stop an alien invasion, or, maybe, just sit around the coffee house and remind us all of a comfortable time, with some people we all consider friends.