..cabin is just as 'noisy' as main Y - there's only a thin sheet separating the two
No, not even remotely.
For starters, you don't have the re###ded parents who let their spawn play videogames or videos without headphones and you don't have the giant families who scream across the aisles.
The hardware in SQ Y is very fine and more than sufficient for me, the passengers are not.