I disagree with what you've said, but I think it's an issue of your frame of reference - You're thinking only in pilot terms.
It *IS* the responsibility of the controller to coordinate. That is spelled out in the 7110.65, and I'm sure a controller who fails to coordinate is going to get at least a talking-to if not some additional training.
However, it is *ALSO* the pilot's responsibility to meet the requirements spelled out in the FAR's prior to entering a particular class of airspace, plus their 91.3 responsibility for everything. The pilot must maintain situational awareness and make sure that the requirements are met prior to entering the airspace, and that means that if you're approaching some airspace and not talking to the particular facility that's in control of that airspace, you'd better speak up.
If an airplane flies right into the airspace while talking to a controller at the wrong facility, the controller has erred in not following the rules spelled out in the 7110.65, AND the pilot has erred in not following the rules spelled out in the FARs. That's why I say "It's everyone's fault." BOTH the pilot and the controller are responsible.
It's this kind of redundancy that makes the system safe. There is no place in aviation for a scapegoat. Everyone must work together and back each other up.