The model is a qualitative one and one should not take the output as quantitative predictions. The bad thing is that there are essentially no scenarios without collapse. I think until around the turn of the millennium there were still reasonable scenarios that could have avoided the collapse but after that even scenarios with unrealistic policy changes and technological advances tend not to avoid a collapse.

I of course hope that the predictions will turn out to be wrong or at least to pessimistic but we surly know that complex systems can unexpectedly change their behavior at the flap of a butterfly.