Question - .git subdirectories

Hello. I'm not sure it's correctly to write to this email address. Sorry if it doesn't. Copy of my home directory stores on external disk under git control. I have devel/ directory that contains some of my old projects with git repositories. But main git repository in root of disk is not tracking and storing their contents. I don't want to use submodules or crutches such as renaming all .git/ in subdirectories. I just want that git treats my .git/ subdirs as plain dirs with any other names. It was already described here: https://stackoverflow.com/questions/2317652/nested-git-repositories-without-submodules. It's very simple functionality but I can't find any simple and right solution. I just want to know is this possible or not? If not possible, then why? Thank you in advance.