In an organization, the number of sequential steps doesn't really scale with number of participants, does it? Rather with dependent steps of the tackled process; say, devise building permit request, await approval, purchase materials, move materials to site, hire workforce, etc.

Theoretically, each of those steps is parallelizable to some extent. Amdahl's law equivalent here would be that some delays are outside the reach of an organization to improve. For instance, a building permit will take the time it takes to be examined based on an external public administration.