These differences are linked to the disciplines' history and the ways that quality and excellence are defined from one academic space to another. It's hard to attribute the differences to specific factors, because the disparity in practices means that each discipline defines what's important to that discipline. That's the case not only for awarding grants, but also for hiring professors. There are obviously still some disagreements within the disciplines themselves, but there's often an overall consensus that emerges about what makes a good CV.
I'd have to go through the history of every discipline to provide a complete answer to the question, but we don't have the time. However, for example, the way that quality is defined in economics is very much tied to American dominance. The good journals are often American journals, and if you haven't published in those journals, people think it's because your research isn't good enough. There are a whole host of factors and dynamics that make it so that different things are assessed and valued from one discipline to the next.