Activision budgets $500m for Destiny. History tells us thats fine right?

Activision has confirmed that Destiny’s 10-year budget is $500million (as reported by CVG News ). Not only will Dr Evil’s finger will be getting quite the workout, that also means Destiny action is pretty much guaranteed for the next ten years. But wait a sec... New IP? Most expensive game ever? Long-term plan for multiple instalments? Why on Earth would this be ringing massive alarm bells in my head