I think the most impressive part of a well-maintained software project, to me, is the ability of the maintainers to keep patches organized and maintain coherent and comprehensive change logs. I can barely manage this in my own four-man team.
in a 4 man team the cost of maintaining program structure is enough to grind everything else to an halt. larger teams on larger projects have an incentive to keep the structure organized because without a clear codebase the project will grind to an halt and have the manpower to delegate maintenance tasks without killing the project speed.
Good to know it's not "just me" then. I seem to have found a balance between "structure that appeals to the business side" and "not placing annoying restrictions on my teammates".