No, you didn't. Until its proven to produce a stable picture for that timeframe without irregular aging related to colors I wouldn't spend money on them.
What do you mean proven ? The drop in luminance is perfectly predictable. When the vendors states a drop in luminance of 20% over 50,000 or 100,000 , that's what you can expect.
For reference, my 50" Pioneer PDP is coming up to nine years, and I can't tell if the luminance levels have dropped (ie. it's certainly not a problem).
There were good reasons why Panasonic and others delayed and then stopped their products during the last 2-3 years.
They couldn't make money. There isn't a mass market for quality TVs.
Cheers