Honestly, I will never wrap my head around how people can happily bring infants on any flight where you can expect people to try and sleep, it’s incredibly lucky if they don’t spend some of it screaming their heads off—I would be mortified if my choices were preventing hundreds of people from sleeping. But I’m not going to rant too hard about that.
Why on earth hasn’t any airline started marketing adult-only flights?
It seems like a complete no brainer to me, I would choose it every time and pay extra for it.
Disclaimer: I may or may not be on a 36h day with only an hour of sleep right now
When I last flew international, my mum took business and the rest of us took economy. There was no noise on economy, but crying babies in business. The reason OP won’t pay extra for that is probably because there is no guarantee at all that it will be any quieter. It is not the same thing as what they want.