It's anecdotal, but I'm convinced I'm not alone here: we've had more Amazon-related failures/outages in 3 years with AWS than we had in 4 years of colo before heading to the cloud because of the exact fear you described.
Even a cloud setup needs good management and contingency planning, and in absence of such it can fail just as hard as a colo setup.
Even a cloud setup needs good management and contingency planning, and in absence of such it can fail just as hard as a colo setup.