Well for rake the breakage was intentional. The Object class shouldn't have been littered with the rake API. After all it was 0.8.7 to 0.9.0.
In Rake 0.9.1 the global API is back, but with warnings this time.
The rake 0.9 beta was out for months, so I am surprised that something as high profile as rails got broken. While framework maintainers are ultimately responsible for their own stuff, the rake maintainer could have pro-actively made an announcement to the effect of "Hey, look out!"
In an ideal world, a continuous integration thingamabob would have sent an alert to rails maintainers about the breakage with the rake beta.
Strike my "0.8.7 to 0.9.0" rationale.