Not all. Atlanta, Barcelona and Seoul were not all that long ago and it's possible that Beijing would be a net win if we ever got to see the real books. The Olympics can be done well. The problem is that mostly Olympics are a tool used by corrupt and/or incompetent politicians who want to line their own pockets on kickbacks or distract the populace from bigger financial problems by claiming that the influx of Olympic money will solve everything.
Sochi was a clusterfuck, Brazil is going to be a clusterfuck, but there's a pretty good chance that South Korea and Japan will be smart enough to have learned from what the successful sites did. And they most definitely will understand the simple concept of asking "Gee, what would Brazil have done in this situation?" and then doing the opposite.