It depends on what you mean by wrecking. Morphine, for example, is pretty safe. You can take it in useful, increasing amounts for a long time. You just can't ever stop using it after a certain point, or your brain will collapse on itself.

This might be a consequence of the bluntness of our chemical instruments, but I don't think so. We now have much more complicated drugs that blunt and control physical withdrawal and dependence, like Subutex and so forth, but the recidivism and addiction numbers are still bad. Directly messing with your reward mechanisms just doesn't leave you a functioning brain afterward, and I doubt wireheading of any sophistication will either.