The issue with the Piker's here is they are very much hand to mouth and not really having time to invest on testing or ideating on things. People who are generally in the setting working on new technology, are doing it with crystals and other etheral type technology. So the older and cheap stuff is left behind, and the Piker's use it because its cheap and don't really have the resources to plow into trying to figure out how to make better guns which took a lot of time, and testing, and it wasn't always a straight line forward type thing (IE you might improve accuracy but take more time, like with rifling, and then figuring out how to do that best took longer... and rifles took a lot longer to make too).
Essentially the Piker's lack the resources to invest in gunpowder weapon development, and the other spires lack the will to as they prefer to invest in improving the safer technology they have.
