No, but it is happening more often. My numbers are a bit skewed as we had several games that started and petered off when the GM saw something shiny (and I admit, I've been guilty of this once or twice when I get excited about an idea, but either it doesn't look as good in action as I imagined, or I find I don't have the time to make it as good as I want). And there have been some games which have been so bad, we didn't continue.
But, now that I have one group that I am the sole GM for, and another where I GM 60-75% of the time, it's happening more. My on the fly ToEE game finished the temple and are preparing for the GDQ series, with the characters 11 and 12. The average level for my Eberron game is 11, and I've started Age of Worms with plans to play to the end. The Eberron game my friend runs has also hit 11.