Because actual quality (usability of research, open access, reproducibility, data availability, sane exposition/introduction, proper methods, documentation and

Because actual quality (usability of research, open access, reproducibility, data availability, sane exposition/introduction, proper methods, documentation and code) is not as important as producing a fancy manuscript. Journals don't care, referees/reviewers might care, but they are unpaid and they usually don't want to rock the boat that much.