In 1992, frame relay was portrayed as an interim technology that would be replaced by Switched Multimegabit Data Service. Today, many believe frame relay will fade away as everyone moves to IP-based VPNs. But don't hold your breath - frame relay will be around for a long time. There are several keys to frame relay's longevity. One advantage is its simplicity.
Frame relay is, in the best sense of the word, a dumb protocol.
There's no extra complexity, and implementations are simple. The frame relay protocol is also efficient. So there's no penalty for using frame relay as the Layer 2 protocol for IP traffic. Frame relay pricing is also simple. The connection-oriented nature of frame relay also contributes to its longevity.