Avoiding accidents by drilling more safely and expensively is not in the interests of BP and Transocean; it makes more sense for them to be risky, gamble 50 times on other wells, make 10x more than they would if they were doing it more safely, and use those profits to cover this one unlucky time.
Forcing them to do it safely even though this makes the well 2x, 5x or 10x less profitable is the purpose of government regulation. In the case of the US oil industry, the regulator is corrupt, completely in thrall to the industry with no accountability.
Hence, the solution is not about pricing risk -- BP have already done that, and this is the logical result. The solution is a regulatory one, which means a political decision.