Actually on servers RHEL is still the default (43% server OS market share), followed by Ubuntu at 34%, Debian at 16% and SuSE at 11%.
https://commandlinux.com/statistics/linux-server-market-shar...
They're talking about billions of dollars of market share, so how does debian get a mention being free? I'm suspicious of their methodology.
At least the infographics down the bottom are obviously full of slop
Enterprises love RHEL because of the paid support, even if they never use it, it's "there".