uh well Harvest Moon isn't an RPG. It never has been. You can try to argue that it is an RPG and point out facets of its gameplay that make it seem like an RPG (such as leveling up or earning money), but the bottomline is that it's a simulation game, and a darn good one at that. If you don't understand the concept of "simulation" games, then you never will.
It's like with Zelda. Zelda is not an RPG. It's not even an action/RPG series. It's an action/adventure series (except for Zelda II).
edit: HERE's the explanation for why Harvest Moon is a simulation, not an RPG:
In RPGs, you develop your character or party through an adventure, but to differentiate RPGs from Adventure games, you are able to improve your character or party through repetitious means, the most common one being battles (although you could use any other means, such as quests, jobs, etc.). Adventure games lack the repetitious means to develop a character (which is why Zelda is not an RPG, no matter how many times Link kills an enemy, he won't develop, he has to find fixed items to improve himself and these are stationed throughout the game in a fixed manner).
In Simulation games, you may or may not control a character, you could be God and control an army of people or anthropomorphic objects, but you do not develop a single character/main character or a party. You may develop a town, a farm, just about anything that your character or army has control over. In The Sims, you are controlling a character, but you develop his house, for instance.
But OoT had Link advancing in power and different weapons, but it isn't an RPG?
Not even NCL considers OoT to be an RPG. They list the game as action/adventure on their website.