Hussar said:The problem is, you are assuming that magic is widespread and commonplace. There is no reason for this assumption. There's no real reason why it isn't true either. It might be, it might not be.
But, only in the last 100 years have we even remotely become "non PoL". Instant communication and rapid travel have only been with us for a couple of generations. Go back more than 100 years in North America and you have a PoL setting despite the fact that we had technology far and away more advanced than what is assumed by D&D.
Even 3rd world countries are more technologically advanced than any 15th century country.
But, even if the 30th level characters "win" this time, in short order, they will die of old age. Then something comes up that tips the balance the other way. Natural disaster, demonic invasion that isn't stopped in time this time, whatever. Now we're back to PoL.
Also, you are assuming that PoL means the entire world. That each and every part of the world is in the exactly same situation. There's no reason for that assumption. You could have long standing, stable nation states in a PoL setting quite easily. Look at the Roman Empire. Perfect example. Everything outside the Empire is PoL and, even within the Empire, there's still lots of PoL places. Other than the city of Rome and a few other cities, you have an entire continent of PoL.
You assumptions are flawed and unsupportable. You are assuming that whenever you get 30th level characters, they will be able to stabilize an entire world. There's nothing to suggest that. At best, they might be able to stabilize a nation or, even a continent. But, after their death, there's nothing preventing dissolution.
If there is a power level such as d&d level 30 and people can't secure their safety in the world they will eventually perish. It is as simple as that. So PoL and d&d level 30 does not make any sense.