I would agree with that statement. The main problem is still simply understanding exactly how the brain works. PRTM I think is just one model that describes a type of functionality, as noted in the article there seem to be many more, and certainly we don't know enough about how the brain itself works. Once we have good well tested models for the functionality there I don't forsee any major problems in holding us back from replicating a brain ie. AI or singularity or whatever.