Why did Bruce Wayne not just purchase Arkham Asylum A lot of Batman plotlines revolve around Arkham Asylum either being so old and run down people escape through old tunnels or crumbling walls, or a little more modern, but so corrupt that those who run the place are villains themselves.

Bruce is a billionaire. I'm sure he probably even owns a few hospitals because he's the head of a giant corporation. Why in the world would he not just buy Arkham and upgrade all the security personally and then be able to literally oversee it in order to be sure the villians he captured serve their sentences?