The end of Scientific Linux

The objective of Debian is not to make software development but build a distro. The great job of Debian is to support multi-arch (many soft just don't compile by default outside of amd64 or arm64, thanks to Debian) and now Debian give more and more the key to build and verify your package (see Reproductible build project). Red-hat keep the key of their building infrastructure.

So Debian and Red-hat are just complementary...