I think you're missing the point. Some of you would like to think that PQ is all that matters in a TV, but in reality, it's a baseless metric. What matters in the real world is "good enough". Is the LCD TV good enough? Yes. Is the plasma better with PQ, yes. But the LCD is still good enough. You're talking about small differences that, for 95% of users, will not be noticed. Most people buy a TV to watch a show or a movie before bedtime or during lunch, and that's about it. Not everyone sits there and stares at a TV and wants to calibrate it to make it pitch perfect.
And sorry, weight does matter, and it does sell. Even if you move your TV rarely, the lighter one will always be attractive because one day, you will have to move a TV, and you don't want it to be difficult. Not to mention, there's a lot of people buying TVs (think younger, 20s crowd) who have the money to spend on a TV, but don't have the stability of a permanent home. Apartments, college dorms, etc.
And not to mention, the black levels... won't be noticed in the majority of situations. You won't watch TV in dark rooms most of the time, it's usually on in the background while work is being done or near bright windows. In this case, vibrance does matter more.
Also, the burn-in issue and the limited lifetime issue of early plasmas.. that definitely helped to kill. Even if it has "gotten better", the first one in the door is the one that wins. And LCDs got the reliability image first.
PQ isn't everything. Practicality also matters.