After thinking further on the utility of alchemy based effects, and firearms in particular, I had an epiphany that perhaps the tactical advantage firearms could bring to Alkenstar isn’t necessarily the kinetic damage itself, though I expect it isn’t insignificant, but the ability to deliver persistent damage effects by tainting the bullet when cast with alchemical reagents.
A rationale for why this strategy isn’t prevalent for more traditional ranged weapons could be that creating alchemical ammunition for them isn’t easily scaled up considering that arrows and bolts have performance requirements that are difficult to modify without adversely affecting accuracy. This isn’t to say alchemical ammunition for those weapons isn’t available, they just come with an item penalty for weapons other than firearms or slings.
This would explain why firearms are the preferred weapon in the Mana Wastes while also being able to scale base damage using inscriptions. Firearms are more effective mundane weapons than their traditional counterparts, but not so effective that adding inscriptions would imbalance them.