How rare are pearls in the real world? If they are fairly rare, what if a change was made to where one could use a 100 gp pearl or a 200 gp ruby/diamond/whatever. Pearls save you money but it you don't have them, you're not SOL.
Personally, I don't see the problem with the identify spell costing 100 gp per item. Generally "cheaper" or less valuable (in terms of their Market Value) items like scrolls and potions can be determined with skill checks like spellcraft. Weapons and armors have a much higher market value so burning 100 gp to figure out what it does shouldn’t be any problem. Even a basic +1 dagger has a market value of 2301 gp. It sells for 1150 gp and 5 sp. Take away the cost of the identify spell, and you make an easy 1050.5 gp. What’s the problem?
Personally, I don't see the problem with the identify spell costing 100 gp per item. Generally "cheaper" or less valuable (in terms of their Market Value) items like scrolls and potions can be determined with skill checks like spellcraft. Weapons and armors have a much higher market value so burning 100 gp to figure out what it does shouldn’t be any problem. Even a basic +1 dagger has a market value of 2301 gp. It sells for 1150 gp and 5 sp. Take away the cost of the identify spell, and you make an easy 1050.5 gp. What’s the problem?