Price, Price, Price would be the reason... they are much cheaper to produce.
Why are LCDs more popular than plasma?
I have a rough time seeing differences in picture quality between brands and models, but the difference between plasma and LCD are overt even to me. When I go to bestbuy, fry's, etc. and gaze at their displays of flatpannels, plasma televisions just look beautiful, despite the reflections, while LCDs just remind me of working on my laptop. Is there more merit to the quality of LCD than I observe or is there some other reason LCDs outnumber plasmas?