>>38164632Guns are probably more of a novelty in the pokemon world. The history of warfare and by extension firearms would be totally different. Napoleon era pike and shot tactics don't really make as much of a difference when your enemy can have a miniature godzilla shooting lasers or a flying dragon.
Thus guns were probably invented later and didn't become nearly as ubiquitous in battle or personal defense, especially since they probably couldn't even fend off certain dangerous wild pokemon very well. Early route birds or a growlithe or two? Maybe. A pidgeot or arcanine? Probably won't put it down in one shot and then you have a very angry monster shooting fire or tornados at you.
The most likely use for them would be in military contexts, where the investment is worthwhile and having a simple to use personal weapon to supplement a troop's pokemon is more needed, and for hobbyists, those who find them an interesting type of weapon and practice with it, even if most situations can be resolved by having your pet mouse shoot lightning at it anyway.