The 787 was unusally noisy compared to the 777 and more so the A330/340 I usually get to fly in.
Electric aeroplanes have electric motors, heaps of people complain about the noise from the electric hydraulic pump on the A320. I know at home my electric fridge, electric dishwasher, electric kettle, electric wash machine are not noise free.
Singapore SID's require 220kts until 4000', 250kts until 10,000' with climb restrictions due inbound overflying traffic.
Singapore never seems to have SIDs when I am there, they just seem to be guidance for radar vectors.
Try a few long haul flights in a 10 across configured B777 and you might change your mind. 9 across is much more civilised.
9 across seats in the 787 is the same seat width as 10 across in a 777.