The above-listed items are all biodegradable - they easily smush and soon become part of the path - so the concept of a garbage can is completely unnecessary. True, the path is then not clear and uncluttered by refuse, but hey, it's the village after all, with everpresent gooey mud; it's never going to look like a swept sidewalk - it's not likely to occur to anyone that would be a possibility!
So with the introduction of packing and non-biodegradable refuse, it takes a really long time to work this wasteful idea of garbage cans into the cultural mindset. Perhaps, rather than 'why are they so dirty?' the question is 'why are we so wasteful?'