It begs the question, why have them at all if they aren't actually treated differently? Especially since some players will ask legitimate questions as to why they aren't treated differently and why they can't use gunpowder itself for other purposes.
I guess my question is "why do they need to be treated differently?" Why do guns need to be different in order to justify including them? Why can't they just be one more weapon choice, no different than the choice between a shortsword and a rapier? Honestly, I have absolutely no interest in unique gun rules for a D&D game. The rules we have right now for differentiating weapons are good enough. What is more, the list of major ranged weapons really could use the addition of guns. It is kind of limited right now, and ranged weapon users would benefit from having the same kind of variety that melee weapon users have.
Of course, the best reason is simply that I think they would be fun to have and I don't have any objection to guns in fantasy. I don't see the need for any other reason.
Also, I never said anything about there being a mysterious lack of gunpowder use outside of guns.
Why not have laser rifles that are also treated exactly like a bow? Why not have a PAK 88mm that is treated like a ballista? Why stop there? Why not a full salvo of an M270 MLRS treated like 12 slingers?
I assume at some point you'd find modeling advanced weapon systems as the equivalent of much simpler systems inappropriate. It would seem I find find that point earlier on the technology spectruum than you do. Are you right and I'm wrong? I wouldn't think so any more than the converse can be stated. But am I unreasonable for not liking them to be treated that way? I don't think so. Am I unreasonable for avoiding games that don't meet my needs as gamer? Again, I don't think so. We all invest a lot of time in a campaign; why invest it in one that is continually offending the suspension of disbelief you are willing to accept?
I think everything here is based on rather strange logic. You are rather arbitrarily saying that guns are "more advanced" than other weapons, and are basing your claim on the idea that "more advanced weapons" must have different rules than other weapons. I don't agree with either.
Guns are not more advanced than other D&D weapons. Historically speaking, they all existed alongside each other for centuries. I thought this point had been well established in this thread. The technology for making guns is no more advanced than the technology needed to make good plate armor and crossbows. Stating that the changeover occurs because of advancements in the "technology spectrum" means you would have to apply the same logic to other equipment in the game, like the rapier or full plate armor. Because you are not, it is simply not a consistent or logical way of looking at things.
As for the idea that more advanced technology requires different rules... My response would be "not necessarily". Sure, a few things need different rules, but only because they have elements that make them behave completely unlike previous weapons. For example, a homing missile may need different rules than other weapons, simply because homing attacks and area of effect attacks work very differently than most default weapons do. However, the level of abstraction the current rules provide can easily cover any less significant change in technology. It is the change in effect and usage that matters, not the level of technology itself.
Ultimately, a gun and a bow really are not very different. The physical principles behind them are very different, but they are nothing more than two different ways of throwing a projectile at an enemy at lethal speed. Nothing more, and nothing less. Why should they have different rules (beyond the normal rules differences, at least) when their basic effect is so similar?
To further address the point that "we need different rules for more advanced weapons", I have to ask how is a laser weapon any different than a Brilliant Energy weapon. Would a Brilliant Energy rifle and a laser rifle have any meaningful differences? Would a laser rifle have any more impact on a setting than a Brilliant Energy bow would (assuming the cost is the same)? I really don't think they would be different at all. Advances in technology and advancements up the chart of magical weapon bonuses are not that different.
As for the game mechanics, I believed I offered my opinion on this exact point some pages ago in this thread, IIRC: the D&D game system isn't designed to span a wide range of weapon capability. I personally don't think it is well designed to handle firearms all that well as do my other players, who as I've said before include a high proportion of engineers and a hunter.
Sure, the D&D system doesn't make weapons feel different all that well. But, as I've been trying to argue, that hardly matters in the case of guns. I honestly believe that, as far as it matters for game rules, guns are more similar to bows than swords are to axes. If the rules for swords and axes work, I don't see why rules for guns would not.
If it works for your group, that's fine but this whole thread was about whether one personally likes firearms and gunpowder weapons. I don't and I've tried to give reasonable reasons for it without simplifying or belittling the contrary viewpoint.
I don't see where I have been simplifying or belittling anything...
As for your reasons... I've done nothing but try to point out why I don't accept those reasons, and why I don't share them.
If you see nothing wrong with treating the firearms as equivalents of non-firearm weapons in your game, go for it. No doubt the firearms you use are considerably more primitive than my examples weapons; they were selected to make a point that there is a spectruum of weapon capability and as setting designers, you have a choice on how to model them and how, if at all, to distinguish them.
I don't think whether guns are primitive or not really has a lot of bearing on this topic. Of course, neither does any discussion of what I may use in my game, if for no other reason than the fact that I don't have a game right now. I've only been talking about the abstract, and perhaps my preferences for the potential inclusion of guns in a rulebook or future iteration of the rules.
To recap my own issue with firearms, they introduce some reasonable questions and expectations from the players. If you aren't going to address them, why bother having them? If you do address them, as many have made clear they do in their own settings, and I assume Eberron does as well, then cool. It's purely a matter of aesthetics at that point.
Eberron doesn't have guns...
Anyways, nitpick aside, I simply don't understand what you mean by "addressing" guns. There are countless ways of implementing guns and gunpowder into the rules and into a setting, some of which may have an impact on the setting, some of which may not. These impacts would have an impact regardless of how the rules for guns may work. And honestly, even if guns were thrown in without anything being "addressed" I don't think it would be a problem for the game.