The article is illuminating but in my opinion the move towards a larger caliber isn’t for raw firepower but rather to provide more room to work with in designing complex munitions.

In other words the move towards a larger caliber is a reorientation towards the concept of the cannon as a platform for not just dumb cannon shells, but for a broader range of sophisticated effects/munitions that may be guided and will likely heavily rely on airburst detonation for maximum effect (larger diameter shell = more space for airburst explosives).

On the other end of the complexity spectrum I also think a larger cannon like this makes sense, a shotgun shell type load optimized for counter UAV fire (a “canister” round) will be more effective the larger the caliber of the shell is.

Higher pressure has often won out over higher mass in the evolution of cannons but we are entering a new era where the role of cannons is radically changing and diversifying, in this new environment there are clear benefits to a larger caliber that didn’t exist before to the same degree.