> I'm ready to bet that is untrue. Sure, no one can recite the code, but people can quickly scan the module and refresh their memory as well as understanding the new changes, even after a while. If not, collaboration would have been impossible.

I don't understand this part. When I was doing freelance consulting, my job was quite often "come to our office, scan this 40 million lines codebase and fix stuff for the next week". It was never a problem to read and get up to speed completely unknown codebases if you have basic programming ability. Much harder to do something that fits floaty business objectives though.