Here's how I reasoned about this, but this isn't my forte and I'd welcome any corrections! The pressure of gas in the bottle neck increases as degassing occurs

Here's how I reasoned about this, but this isn't my forte and I'd welcome any corrections! The pressure of gas in the bottle neck increases as degassing occurs but only until an equilibrium is reached. The equilibrium occurs at a pressure lower than that required to deform the tough plastic in the neck of the bottle and lower than that required to overcome the soft bottle body plastic connected by hydraulic advantage to the gas via the small cross sectional area of fluid in the bottle neck.