Even if the current seat were technically good to go for another 10 years, the physiological effect of not changing anything is going to hurt them.

Even if the new seat is nothing revolutionary, whatever is new about it that justifies designing and producing it in the first place must be enough to justify retrofitting it. Otherwise why don't they just fit the same 2007 seat in the a350 too? (And slowly alienate their core client base over the next 5 years)