The problem is that it's expensive to do experiments. Most require grants to pay for it. I can't imagine that most of the institutions paying for science are going to okay millions of dollars to repeat an experiment twice more. As it is, it's hard to get a grant for anything but applied science, and even then they want to know what the results are before the experiment is done. Point being that while imperfect, peer review is at least happening, and repeat experiments probably won't really happen unless it can be done for $20 or less.