“Economy of scale” describes how things can get easier when the organization is larger. Even small towns have post offices. If a tiny town grows a little bit, it may still be supported by a single post office, but it will take proportionately fewer resources of the town to run it. In this way, it’s easier for a larger town to run a post office. The same could be said for operating a hospital or a school.
Economy of scale provides an incentive for growing. The trouble is, just because it’s easier to run something doesn’t mean it runs better. Perhaps worse still, if something has to be “large enough” to work at all, “small” can be shut out. And some of the most important and valuable efforts are small, individual ones.