Outside of fields with direct penalties for invalid science (think aviation, nuclear reactors, sinking boats, collapsing bridges), we're just relying on the integrity and honor of researchers. On an individual level it's much more effective to cut corners and publish trendy research than it is to make valid science.

The situation is only made worse by the fact that universities reward this; because they too are rewarded more for high-profile research than they are for scientific validity.

My guess is that most studies in softer sciences are simply erroneous. Many social sciences have already been shown to be unreliable by the replication crisis.

My personal experience comes from reviewing hundreds of published studies that evaluated the applied effectiveness of machine learning models. Half had significant statistical errors.