> However, I don't think most (any?) researchers are actually ignorant of those problems. They are actually doing research somehow, so they've figured out the game well enough

The problem is that "winning the game" is about publications, tenure, and (less important but increasingly also) popular recognition, rather than about the size of your contribution to valid research results (one hopes that publications and tenure correlate, and yet...).

So, getting results of dubious validity published, and covered in popular press, can be exactly "figuring out the game well enough", an end in itself, rather than a minor step toward a research program.

You are right that I don't want to assume bad faith in any individual instances, and yet... here we are, in aggregate.

What are the costs? I dunno, mis-education of the popular audience, for one, I guess. Maybe that doesn't matter, but, it kind of does? And the opportunity cost of all the scientific labor being spent on "easiest to publish the most times" instead of what might be highest priority to discover. And the aggregate collective effect of a scientific community enabling each other on that.