Those bad papers are an impediment. It's much harder to get your paper/proposal past reviewers when it's for solving a problem someone else claims to have solved already. Also, even if you do get past that higher barrier at an added expense and time (reviewers will want a lot more evidence to support a claim refuting a prior claim versus a groundbreaking new claim), the person who usually gets cited more, funded more, and a bigger career advantage is still the person who's non-replicable publication was first.