I don’t think it’s as the backrest is as “complicated” as you think. The lower leg portion has some subtle mechanics going on as well.
Here’s a sh0rtened loop of that segment; it’s easier to see if you don’t have to watch the whole thing… IMO.
http://www.tubechop.com/watch/405940
I can see to make something similar would be using several separate mechanisms (linear actuators and sliding mechanisms).
If this seat frame, manufactured by Ceratizit, “… for the Business Class seats of a leading aircraft manufacturer” is any indication, I think you are correct.
Cool stuff going on here, check out the axial recirculating ball bearings (upper left) adjacent to the bracket with the printing on it. Manufacturers note states many components are titanium.
Moving your question to “Transportation”, we’ll see how if flies there… … . .yeah, I know… . 