From my experience not all enterprise software is designed or packaged with Debian in mind.
Some of the tools I installed and supported are RHEL first and RHEL only software which require exacting ABI and even library versions to run correctly.
Debian is a great server, and has great support, but being one of the best doesn't always cut it.
Doesn't this fragmentation of RHEL clones mean that this exact thing will have to change? Not from Debian perspective, but others ignoring Debian and other distros and treating RHEL as a "linux standard" will have to often be revised.
I don't think so. These are extremely expensive software packages, generally bought by corporations with very big budgets.
These people either pay Red Hat good money for license, or pay good money for a sysadmin who knows what they are doing and install this software on a RHEL downstream distribution.
Sometimes you get a package deal. Hardware + RHEL + software package, which serve a group of engineers or researchers.
IBM is after this revenue. Universities and other research institutions won't care on the long term, because they can migrate piecewise, and group by group. They don't have an official favorite. They use whatever they like and works on their computers generally.
However, bigger research communities like national HPC centers, CERN, NASA, etc. used RHEL and alike, because they get unofficial, sometimes free or almost free support from Red Hat themselves, and they have a sizeable stack built on top of that.
They can and some of them will of course migrate, but it'll take time, and create pain down the road. We'll see.
Some of the tools I installed and supported are RHEL first and RHEL only software which require exacting ABI and even library versions to run correctly.
Debian is a great server, and has great support, but being one of the best doesn't always cut it.