Debian and Monolithic Networking Configs - Why?

When it comes to config files the Debian people and I agree on basic principles - we’re both keen on applications having a directory where you drop multiple config files to allow for easier deployment and management. Even if they do sometimes seem a little… over zealous (Debian developers? Never!) and you end up with the split Exim4 configs.

So one of the little quirks that I’d like an answer to is, why does Debian have a single big interfaces file and no support for a directory of files? Something like the eth0-cfg files Red Hat uses. It’d make adding additional interfaces a lot easier and would let me use puppet to manage them without breaking in tears every time I try and write a native type for it.