Longevity can only be proved by time, but the same applies to LED backlit LCD as well, it's not been about long enough to have proved it's longevity either.

Both Plasma and CCFL/LCD published estimated life spans, based on the light output dropping to a certain percentage of it's original value - however, this was a complete 'guestimate', and completely irrelevant as most fail long before that point is reached, and almost always for entirely different problems.

I guess it's just lucky that manufacturers now ensure we update our equipment usually before the MTBF is reached for the panels - by cleverly introducing smart features that will stop being supported after 18-36 months they've reduced the time before replacement is likely.

Add in the next must have feature every 18 months and it's now almost irrellevant as to how long a TV will last as many will have replaced it due to other reasons, that may or may not be legitimate reasons to replace.

I think as long as the TV produces a great picture all other add on features should be considered short term freebies so when nothing smart works in 3 years time you won't be too upset

At least OLED is not all power consuming and hot running like a plasma that even good quality electronics driving the screen could end up with a heat shortened life.