I think one of the main reasons it's still used is that the enormously popular cPanel/WHM requires CentOS or RHEL. It's a line of software that does system admi

I think one of the main reasons it's still used is that the enormously popular cPanel/WHM requires CentOS or RHEL. It's a line of software that does system admin for you, which takes care of a lot of the PITA parts of CentOS. Not that I recommend CentOS, I prefer Ubuntu, but I think that explains the main appeal, at least among web hosting services.