I guess you just don't agree with me and that isn't bad, but the thing is I'm not really wrong. It's not really a matter of opinion.
To give you an example. A balanced economy system is one that will allow a player to have everything he wants if he works really hard for it. If he skips most stuff he's not going to have much stuff either. If he does something on the side, thus works more then he'd have everything he needs (not everything he wants, just everything he needs). It is a simple correlation of time investment = profit. Although there should also be a risk factor added to the equasion but we'll keep it simple for the sake of the example... You call this grinding but you are wrong or at least you might just be getting me wrong. What i mean by this is that if you do all side quests (or nearly all as some might be mutually exclusive or you might just not have the required skills to get some) and explore the whole map or almost all of the map you should get money to get everything you want. Why is this not grinding? Well grinding is going over and over the same area each time it respawns for more loot and that is not what I am saying to do at all.
You say you go exploring and it is profitable for you. How is it possible? Well actually I can see how it is but I'll get there in a moment. You do the main storyline quest for that area, loot and sell. Then you go and do the side quests and explore the area around that place. Loot and come back to sell, only that there is nothing to sell anymore, the merchants already bought everything they would have bought from you! How can you be making any money at all except for a few scraps (which are not really worth it just by themselves) that they might pay you directly from completing the quest? The answer is you don't make any money, not unless you take so long that the merchants already respawned the inventory and even then you only sell some of the stuff, most of the stuff you just still won't sell even with smart looting... Now why is it that sidequests and exploring are giving you money? Because you are very likely doing them before the main quest. Which is normal, I do it too, leave the main quest for the end. But what this means is that you do a side quest or two, merchants won't buy more from you, then when you finally go do the main quest you cannot sell anything you got because the merchants just won't buy more! You could have just done the main story line and get the items and sell them and that was how much you'd get from the merchants anyway.
You do are right that players will always find ways to game the game. There is no such thing as a fool proof system and if someone could make one, they'd look for cheats or mods to get around it. That doesn't means you shouldn't strive for a more balanced system.
And I understand that you will most likely still play several times and explore everything with every single character, do as many quests as possible. This is alright, but tell me how many people do you realisticly think will do it as you do when the game discourages them from dong anything aside the main storyline? Because really, they will not be rewarded and I know quite a few people who play CRPGs and you know how it goes. If there is something they could do but it's not worth it, they won't. To them it is a waste of time, they did it once and that was all it took to know what is there. People like to be rewarded for their time. Think of it like in real life. Would you keep doing everyone favors for nothing? Cause if you would basicly you'd have no life of your own. To the same degree, players in games don't like to see their time wasted. Most don't at least. I know some don't mind but most of them? They are just going to ignore anything that doesn't really rewards them.
The replayabillity of CRPGs is trying different builds. The first time is about discovering all there is to discover yes, but after that it's all about trying different builds and seeying what is really fun to play with. You may like to go and explore but exploring is about discovering new things about the game. If you already know them, you are not really exploring anymore, you are merely going there for the sake of going there. If this was a proceduraly generated game, sure, i could understand that, but it's not and in fact it's probably not possible or at least I don't see it being viable to build a CRPG that is proceduraly generated anyway.