There will always be shitty studies out there. With the proliferation of these pseudo-journals there will be even more bad science out there. This science is a waste of time of money but I don't think it poses much of a direct threat to progress. The bulk of the wrong studies are likely also the obviously bad and unintersting studies. These are the studies that nobody reads. The quantity of genuinely significant work (stuff that pushes forward a field) is tiny. When something that looks like this comes out it is immediately mobbed: people rush to reproduce the results and/or use the new techniques. If it's wrong we'll know very soon. In practice there is always an attempt to replicate the important stuff, even though the publish or perish nature of science means that pure replication studies are rarely carried out and instead are dressed up as a minor extension of preceeding work. The lesson is that it's dangerous to treat a single study as definitive. Wait for the field to catch up and, where appropriate, wait for the meta-studies.