[l33tman]

Decoherence theory is really somewhat orthogonal to the measurement problem. Decoherence explains how the "collapse" happens gradually if you have a non-perfectly isolated system by seeping entanglement. But at some point you still need to activate the stipulation that you as an observer is drawn into the entanglement and at that point whatever's left of the wavefunction "collapses".

In essence the Copenhagen interpretation is still correct as a simplification that can still be OK in most cases. This is reflected by the fact that practising solid state physicists have successfully used this 20's style of QM for 100 years now.