A few things
Firstly there were a LOT of poor Plasma and LCD TVs out there until more recently, even from premium brands (ever seen a Sony S series LCD , they were rubbish, more later).
Bad colour banding on Plasmas, some strange artifacts. Poor upscaling on LCD, strange colours, motion blur, slow response. It really was a minefield.
Plasma TVs really came down to Pioneer and Panasonic, the big Pioneers had an excellent picture, the Panasonics the best of the smaller / cheaper ones.
LCDs well there are some good ones, best example of you get what you pay for was the above S Series Sony, same display, same source via HDMI there were 3 other TVs, 1 similiarly bad from Sony, and two others both excellent, both looked much nicer and one of them full of toys, the cheaper good one was the second most expensive TV but the best value. Oh and it was also a W series Sony (OK it was the entire 46" range of Sony LCD TVs and it was a case of two terrible two excellent)
So these LCDs were the first I thought that is good enough to replace CRT, or be an alternative to a decent plasma.
Shopped around and found a TV between the two good ones, not again, but a lot better at SD than either ot the other two good TVs, anyway I went LCD myself.
So Plasma was killed by power consumption, weight, screen burn (my main concern), and some poor ones, LCD finally took off with enthusiasts when the decent 1080p panels became affordable.
Even Pioneer dropped out of the UK market, their TVs were nice but some were not full HD, sad to see them go.
Panasonic kept going until basically is was not worth doing them.
Idiots carried on buying the cheapest flat screen they could, some real shockers out there, even some premium brands like the above crap Sony S series. Enthusiasts moved to the better LCDs, a good example being Sony, they sold a lot of W series, their enthusiast range. The Koreans pulled their fingers out and took the whole middle market. Now they are taking the rest from the Japanese. Samsung and LG being the leaders.
I have relations who are big Panasonic fans and I know they have Panasonic LCD TVs.