Motive

In lots of fantasy campaigns there's just no reason for the dungeon crawl; or for continuing to adventure once a certain level of wealth is attained.

When you're richer than the king, do you care if you're just fifth level?

In Magic Returns, I'm working on motive.

First.  Why are there dungeons?  First, they're not dungeons.  They are vaults.  The cyclical nature of the mana level created a need to store valuable magic items while the mana dropped to zero to prevent them from being damaged or lost because they were confused for something mundane.

The exceptionally long zero period the previous cycle had caused the collapse of society and the loss of many of these vaults.

Second, other than greed, why adventure in the first place?  It's an open secret of the mage's guild they seek very high mana zones to occupy.  Cash and knowledge rewards are given to mages who find and secure such zones.  Animals with magical metabolisms also seek such areas as they tend to not give up all of their magic during the zero times.

The Gods mandate the spread of civilization.  It is the duty of the priests and acolytes to bring the proper methods of worship to the barbarian wilderness.

This Holy Mandate has an effect on the mundane as well.  If you can carve a place out of the wilderness, secure it and hold it for five years the Princes will ennoble you and create your fief out of your holdings.

Of course, there's always good old fashioned greed; unfortunately this is a society without a middle class.  Social statuses of 0 or 1 are still commoners and cannot own land except under very limited circumstances.  A commoner's rights to own property and wealth are somewhat truncated compared to most nobles (taxation is very high).  But don't despair; there are several paths to nobility and one of them is flat buying a title.

The campaign TL is 1, bronze age.  One of the principality city states has achieved TL2 and there are a fair amount of TL3 items surviving from before the last zero time.

TL2 iron armor is made (x2 cost) but bronze armor is far more popular despite its 4x cost.  The reason (motive) is status.  Iron armor is more suited to mass issue to soldiers and city guards; bronze is a status symbol.  Recall that dressing and acting below your present social status can easily result in you becoming a member of that lower rank.

Iron weapons, on the other hand, are prized.  As are steel.  The TL3 steel weapons that have survived are nearly all highly decorated so will be far more expensive than the mere x4 TL differential.  This is because the weapons that are issued en masse aren't status symbols like swords but rather things like spears.