Peer review is not part of the scientific method. In most fields, for example physics, it is a new thing, and wherever it has become a standard thing, we see stagnation.
Peer review keeps out cranks, but it also keeps out the impious. It makes it safe for a science to become a religion, and for scientists to become priests of a state sponsored theocracy. Cranks have never been a threat to science, state sponsored theocracy has always been a threat to science, thus peer review has always been a failure. It is caused by science becoming theology, and causes science to become theology.
Back in the days when physics made dramatic progress, there was little peer review, perhaps none. For example, “Electrodynamics of Moving bodies” was not peer reviewed, and my guess is that today it would never have passed peer review – because it was written by a patent clerk, and was in large part a novel way of looking at results that were a hundred years old. Outsiders, and novel ways of looking at things are pretty much guaranteed to fail peer review.