The 6S/6S Plus beats it at a 7year life (released Sep 2015).
I sincerely hope that as we are getting to much faster chips (A15 is a beast) and not so many hardware dependent software features every year, these life cycles would improve.
and why keep it then on all of their computers? because it's useful.
it's nice to have bt headphones while i am biking, but i surely dont need it on a 6h train ride. it's just another thing to keep charged and it has happened that i needed it right after it went empty. perhaps i should by 2 pairs?
just because a lot of people stopped vocally moaning about it, doesn't mean it's not gonna be missed. magsafe came back from the dead, this will one day too :}