Red Hat use to have a distribution for everyone. It was one of the most popular Linux distributions. Then it moved to Red Hat Enterprise, and that really caused many of the Linux users to find something else and switch. Fedora is nice and all, but it felt like Red Hat throwing a bone.
Ubuntu came up and took its place as the distribution for everyone. Red Hat got stuck in the stuffy enterprise market.
As most people who know, Enterprise software means over priced software, that barely works, but somehow it makes executives feel good about using it, probably because they need a full IT Staff just to keep it running.
So companies who want to follow the buzzards of agile and nimble, have swapped to non-Red Hat based systems.
Nothing technical, just bad PR from Red Hat, that made them loose their fan base.