Communities of free-living organisms are shaped by processes operating within and among patches of habitat, while pathogen communities are shaped by analogous processes operating within and among hosts. Resource competition (R) theory can describe dynamics within patches or hosts, while metacommunity dynamics describe competition-colonization tradeoffs, extinction debts, and superinfection. However, models at this broader scale often assume instantaneous competitive exclusion in co-inhabited patches or coinfected hosts. Impacts of more gradual competitive exclusion on the abundance, distribution, and diversity of species are less clear. Here, we nest a general resource competition model within a metacommunity framework and manipulate the relative timescales for processes operating within and among patches/hosts. We focus on superinfection in pathogen communities. We compare cases where transmission depends on infection prevalence versus the abundance of pathogens within hosts. Surprisingly, slowing the relative pace of competitive exclusion within hosts can decrease infection prevalence of the inferior competitor and increase prevalence of the superior competitor, depending on transmission and virulence. Slower dynamics reduce the abundance of both pathogens within hosts and promote diversity at multiple scales: coinfections within individual hosts and co-occurrence in the host population. These results highlight surprising feedbacks that can emerge across scales and reinforce the rich cross-scale connections between community and disease ecology.