Hah, people would find a way to hide some novel findings in an otherwise "negative result" paper and then extensively cite it in all future papers.

Earn more words via replicating. Start with enough words for one paper.

The lifetime word limit is a too rigid constraint. There should be a possibility to acquire (or lose) the points you can later use for publishing your results. Then the "price" of publishing negative results could be lower than other results.