Not in academia myself, but I suspect the basic issue is simply that academics are judged by the number of papers they publish.

They are pushed to publish a lot, which means journals have to review a lot of stuff (and they cannot replicate findings on their own). Once a paper is published on a decent journal, other researchers may not "waste time" replicating all findings, because they also want to publish a lot. The result is papers getting popular even if no one has actually bothered to replicate the results, especially if those papers are quoted by a lot of people and/or are written by otherwise reputable people or universities.