That's the reason why I have to verify what inconsistencies Eberron hides behind its wonderful scenario, and I'm asking help to the EnWorld crew to find (and possibly solve) them beforehand.
This is probably an exercise in long-term futility, because I remember one such thing came up on the WotC Eberron boards. Someone asked, "Why are Valinar Horses so expensive?"
The answer: "Because the elves don't sell them."
Reply: "So if I horse-thief some of them, and start breeding them, I can make a mint."
Answer: "The horses ridden in battle are fixed. Only certain breeding stock is kept in secret places."
Reply: "So, I have a druid and he casts Regeneration and Heal. Horse is now healthy and can reproduce. I use Dominate Animal to make them breed. Can this work?"
Answer (from Keith Baker himself in a Dragonshard): "The horses have some kind of spiritual connection with the elven heroes of the past. Attempts have been made to breed the horses, but only the elves seem to have the understanding or the knack to ensure success."
And that's just the example I remember. All settings have things that are story-wise awesome, but game-mechanical *whu?* Too many to ever really fix, especially with more rituals and powers being released all the time.
Best thing to do is to strike a gentlemen's agreement with your players. If they bring up a good point, give them a small reward for clever thinking, but don't let it break the world.
Well, it looks like they have 15 CL spellcasters (where are they???), so it doesn't appear to be so impossible to imagine a 17th level spellcaster in 1000 years.
These inconsistances can be mitigated, depending on how much you are willing to hand-wave things for NPCs.
For my Eberron campaigns, I've said something like:
"I know the description says a 15th level caster, and that's what it would take for you to build it yourself. But with 75 1st level magewright assistants, a particular dragonshard focus item, a dragonmark heir of the proper mark, and 3 years of work, a 9th level caster can do it. How many of those items do you have access to?"
There would be mass-rape and atrocities back then. The PTSD effects would be greatly magnified, I would think.
I wonder if anyone has made a serious study of the matter. Did soldiers returning from the Civil War have all the same issues that soldiers returning from today's wars do, or was it somehow different? (We certainly have evidence that the mindset of the USA was different back then, but did it have any effect?)
I dare say people didn't talk about such stuff back then: you suffered in silence. People would be equally as tramatized, but you got drunk and beat your wife in the privacy of your own home and no one ever spoke of it.