Why Hasn't the DVI Interface Replaced D-Sub?

nic1m asks: "When DVI connectors started appearing on video cards I thought they were a smart replacement for the old D-Sub analog connector because DVI can support both digital and analog displays. With LCDs rapidly gaining market share I would have expected DVI to replace D-Sub by now. Almost the opposite seems to be happening, however. Many video cards still lack DVI, most LCDs still have only an analog input, and motherboard-based graphics never have DVI. Why has DVI been a relative failure in the market?"