It doesn't reflect any decision so much as it's just the way it is right now. Those two handles happen to scale down nicely to match (both in terms of fit and balance) with knots intendedd for 24 mm sockets. That said, I'm pretty sure we have more demand for larger sizes.
I look at my modest 3 brush collection; now crowned with a Lotus and remember when possessing 3 brushes seemed immodest. My tastes are catholic ( wide ranging, not high church) but people with specific configurations need to practise patience and restraint. To many folks are grabbing what chance allows with curious strategems of future trades. This just fuels like behaviour and an aftermarket with potential for scalping and ill will. If you do have a particular brush in mind wait for it. Paladin production is slowly increasing and YOU have just as much 'luck' as the next guy.