So you are telling me that the lack of guides, architecture docs, engineering notes etc. for the software you are working on is not preventing the software from

So you are telling me that the lack of guides, architecture docs, engineering notes etc. for the software you are working on is not preventing the software from being successful and generating a high ROI. In other words, you just proved my point. The fact that it is a pain in the ass for you working on it has nothing to do with the ROI of the software. Think like a business person not a developer.