I have played some grinding games in my life and as always the market regulates itself. People are trading ingame currencies outside of the game world (ebay and such), they offer leveling services where they take your character into a high level party to make it level up, they trade items, even full accounts with multiple characters inside.
If you feel abused by the game or its developers maybe you shouldn't spend time playing and find yourself something else to do, because you can get exploited in most activities.
Not players who are abused by games or game developers, but they misuse themselves by letting themselves be addicted and letting themselves get entangled in many things including spending a lot of money to buy raise levels as you stated. Spend many hours just to stick around the games without care about anything else in your life.