Yes, and when local governments lack the power, desire and/or resources to protect heritage sites, can the larger world community step in, and how? Perhaps start by buying the land where such sites are located?
Sure, the private-property solution can work well, as can active governmental protection. In this case though, Belizean laws made the destruction easy. This monument was on private property, but the monument itself was under government "protection". The owner of the land had no incentive to protect it.