I don't think that there is a necessary connection between the risk and the reward. Sometimes the risk is low and the reward great, or vice-versa. We should analyze both aspects in each individual case on their own merits.
In this case, I think that Amare constitutes a huge financial risk due to his contract, lack of insurance, and health. Even in the best case scenario, I don't think his talent justifies such a risk, especially when we look long-term. It's admittedly a judgement call.