Journals are typically interested in publishing novel results. Why would it be a problem if studies which find that a drug works as expected are not published, as long as they are still submitted to the FDA and assessed there?
Nobody's saying that journals have to publish every study, just that the data should be available for review. That's so bedrock a principle of science that it's hard to imagine a credible argument against it.
This is a quintessential problem between public and private research.
# find that 2 or 3 of them beat another placebo by a "statistically significant margin"
# publish those 2 or 3 studies, throw away the rest
# Get your placebo FDA approved, patent it, get the advertising department into gear and start selling your placebo to the public