Mostly because I don't believe items would really add anything to the game- I can't really find a compelling reason to include them. Also most RPG games in my experience lose the money balance very quickly- like a quarter to halfway through the game the player accumulates so much money that they can buy pretty much anything.
Items always have a very important role in RPGs.
1. Items as reward: it is just satisfying to find new and better items after a challenge as reward.
2. Items as progress-key: Items are often used as obfuscated keys to progress to new areas (craft X and use it on Y to receive new monster Z).
3. The collector in us: Many people like to collect items, it is a very strong motivation in RPGs for some people.
4. Items as character progression: Same RPGs just use items to represent the progression of the player character (aka gear based).
5. The businessman in us: Some people like to trade/buy/sell items to gain more money.
Money is just a convenient way to compress large amount of items which are no longer useful for the player, but useful to users (trader).
I'm not sure if your reasons against items are honest. Well, I tended to exclude some aspect in my game, because I wanted to avoid the effort to code and maintain it. In this case I often thought, that it was actual not really neccessary to include this feature, and I looked for some reasons to support this assumption. Eventually it didn't work like this. If you want to leave something out, you should think about why it is really uncessary. The same for adding new things, is it really necessary to include X to support your core game mechanism.
But in your case you take an existing, successful game design and removes some parts, which could break down the whole design.